Est. 2005 · ISO 9001 Certified
Premium Sight Glass & Level Gauge Glass Solutions
Manufacturing high-performance borosilicate, aluminosilicate & quartz gauge glasses for boilers, chemical reactors, oil refineries, and pharmaceutical equipment. Custom dimensions, precision engineering, and globally trusted quality since 2005.
- ISO 9001:2015
- DIN 7081 Compliant
- ANSI B16.34
- Material Certificates
- Full Test Reports
Factory-Backed Strength, Global Supply Capability
As a direct manufacturer — not a trading intermediary — we control every aspect of production, from raw material selection to final quality inspection. This ensures consistent quality, competitive pricing, and reliable delivery for our global clientele.
In-house capabilities: Glass melting · Precision cutting · Edge grinding & polishing · Thermal tempering · Surface treatment · Laser etching · Quality testing · Custom packaging
Industry Solutions
Tailored Sight Glass Solutions for Every Industry
Power Generation
High-temperature gauge glasses for boiler drums, superheaters, and turbine systems. Withstanding extreme thermal cycling in coal, gas, and nuclear power plants.
Chemical & Petrochemical
Corrosion-resistant borosilicate and quartz glass for aggressive chemical environments, reactor vessels, distillation columns, and solvent storage tanks.
Oil & Gas
Heavy-duty sight glasses for pipeline inspection, separator vessels, and storage tanks. Designed for high-pressure hydrocarbon service with certified pressure ratings.
Food & Pharmaceutical
USP Class VI compliant, non-porous gauge glasses for sanitary process equipment, bioreactors, and sterile mixing vessels. Easy to clean and sterilize.
Marine & Shipbuilding
Shock-resistant and vibration-tolerant gauge glasses for shipboard boilers, ballast tanks, and fuel systems. Compliant with major classification society requirements.
General Industrial
Versatile sight glass solutions for HVAC systems, water treatment plants, hydraulic reservoirs, compressor oil level indicators, and general process monitoring.
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Level Gauge GlassAluminosilicate Reflex Gauge Glass
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Level Gauge Glass
Aluminosilicate Transparent Gauge Glass
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Level Gauge Glass
Borosilicate Reflex Gauge Glass
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Level Gauge Glass
Borosilicate Transparent Gauge Glass
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Level Gauge Glass
Quartz Reflex Gauge Glass
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Level Gauge Glass
Quartz Transparent Gauge Glass
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Level Gauge Glass
Soda-Lime Reflex Gauge Glass
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Level Gauge Glass
Soda-Lime Transparent Gauge Glass
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Tubular Sight Glass
Red Line Tubular Gauge Glass
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Tubular Sight Glass
Standard Tubular Gauge Glass
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Circular Sight Glass
Borosilicate Round Sight Glass
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Circular Sight Glass
Flange Round Sight Glass
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Circular Sight Glass
Quartz Round Sight Glass
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Circular Sight Glass
Round Sight Glass with Hole
Why Choose Aohong
The Manufacturer Advantage You Can Trust
Direct Factory Pricing
Eliminate intermediary markups. As a manufacturer, we offer competitive ex-factory pricing with full transparency — no hidden costs, no trading company margins.
Custom Manufacturing
Any size, any shape, any specification. Send us your drawings or samples and we will replicate or engineer a solution tailored precisely to your equipment requirements.
Fast Turnaround
With 6 dedicated production lines and substantial raw material inventory, we deliver standard orders in 7-15 days and custom batches in 15-30 days — reliably.
Rigorous Quality Control
Every batch undergoes thermal shock testing, dimensional inspection, surface quality checks, and pressure testing. Full material certificates provided with each shipment.
Global Logistics Network
Exporting to 50+ countries with reliable sea freight, air freight, and express courier options. We handle export documentation, customs clearance support, and secure packaging.
Dedicated Support Team
English-speaking engineers and sales representatives provide pre-sales consultation, technical drawings review, and after-sales support — ensuring smooth communication throughout.
Request a Custom Sight Glass Solution Today
Looking for the right sight glass for your equipment or project? We help you choose the most suitable material, size, shape, and performance requirements based on your operating conditions. From standard models to custom-made solutions, we support industries that demand reliability, precision, and long service life.
Deep Material Knowledge & Precision Engineering
With nearly two decades of specialized focus on industrial sight glass manufacturing, our engineering team possesses deep metallurgical and materials science expertise. We understand the critical interplay between glass composition, thermal expansion coefficients, mechanical stress tolerance, and chemical resistance.
Our glasses are manufactured to meet or exceed international standards including DIN 7081, ANSI B16.34, and JIS B8210. We utilize advanced melting and forming techniques to ensure bubble-free, stress-free glass with exceptional optical clarity and uniform thickness.
- Glass Types: Borosilicate 3.3 · Aluminosilicate · Quartz · Tempered Soda-Lime
- Temperature Range: -40°C to +500°C (-40°F to +932°F)
- Standards Compliance: DIN 7081 · ANSI B16.34 · JIS B8210 · EN 10204 3.1
Our Happy Clients!
“We’ve sourced gauge glasses from SightGlass Pro for over 7 years. Their consistency in quality and on-time delivery has made them our primary supplier for boiler glass across all our facilities in Southeast Asia.”
Procurement Director
“The custom reflex glass they produced for our chemical reactors exceeded expectations. Exceptional clarity, precise groove machining, and excellent chemical resistance. Highly recommended for demanding applications.”
Chief Engineer
“Quick response, professional communication, and the quality of their sight glass discs is outstanding. They helped us with a rush order and delivered ahead of schedule. A reliable manufacturing partner.”
Operations Manager
Quick Answers About Our Gauge Glass Products
Frequently Asked Questions
Our gauge glasses are manufactured from premium borosilicate glass (3.3 expansion coefficient), aluminosilicate glass, and high-purity quartz glass. Each material offers distinct advantages: borosilicate provides excellent thermal shock resistance (up to 500°C), aluminosilicate offers superior mechanical strength, and quartz delivers exceptional chemical inertness and UV transparency. We help you select the optimal material based on your specific application.
Absolutely. Custom manufacturing is at the core of our service. We produce sight glasses and gauge glasses in virtually any dimension — from small 25mm diameter discs to 2000mm long strips, with thicknesses ranging from 5mm to 50mm. Simply provide your technical drawings, CAD files, or physical samples, and our engineering team will match your specifications with tight tolerances (typically ±0.1mm for critical dimensions).
Standard catalog items ship within 7-15 business days. For custom-manufactured orders, lead times range from 15-30 days depending on complexity and volume. We maintain substantial inventory of popular sizes (especially 280mm, 320mm, and 340mm gauge glass lengths) for immediate dispatch. Rush orders can be accommodated — please contact our sales team for current production scheduling.
Our factory is ISO 9001:2015 certified. Our gauge glasses comply with DIN 7081 (German standard for gauge glasses), ANSI B16.34 (American standard for valves and sight glasses), and JIS B8210 (Japanese industrial standard).
We use multi-layer protective packaging specifically designed for fragile glass products. Each piece is individually wrapped in protective film, separated by foam dividers, and packed in reinforced export-grade corrugated cartons with plywood reinforcement for larger orders. Our packaging has been tested and refined over 18 years of global shipping, with a damage rate of less than 0.3%. We offer sea freight, air freight, and express courier (DHL/FedEx/UPS) options.