How to Choose Traffic Light Size: 200mm vs 300mm
Start with the size specified for your project or existing signal head. Then match the indication, electrical input and installation drawing. This checklist helps you compare GAOQIAO's 200mm and 300mm ranges before requesting a quotation.
Updated 5 October 2026 ยท GAOQIAO Traffic Technology
200mm and 300mm: what should you compare?
| Item | 200mm / 8 inch | 300mm / 12 inch |
|---|---|---|
| Size designation | 200mm catalogue size class | 300mm catalogue size class |
| Published complete-head example | Three-aspect ball signal | Three-aspect arrow signal |
| Published housing example | Four-section replacement body | Four-section PC housing |
| Before selecting a model | Confirm the approved optic size, required indication, electrical version, housing dimensions and mounting arrangement. | |
The examples above have different indications and supply scopes. Choose the indication your signal schedule requires, then compare models within that configuration. A housing quotation should state which modules and mounting parts are included.
1. Check the project specification
For a new installation, send the destination country, applicable project specification and approved signal layout. Review the required optic size, photometric documents, mounting position and approach geometry with the project designer.
Road type alone does not establish the correct size. Nominal diameter also does not establish a fixed viewing distance or compliance with a particular standard. Request evidence for the exact model and configuration.
2. Measure an existing head before ordering a replacement
Record the label and take clear front and rear photos. Measure the module's outer diameter, rear depth, fastening points and sealing interface. For a complete-head replacement, include the housing dimensions, bracket spacing and cable entry.
Inch labels identify catalogue classes. Use millimetre dimensions on the approved drawing to confirm fit. Two products described as 200mm, or two described as 300mm, can have different rear profiles and mounting interfaces.
Use the module versus complete-head replacement guide to define the parts you need.
3. Confirm the indication and electrical version
Specify ball, arrow, pedestrian, bicycle or countdown indications, plus the number of sections and required sequence. Confirm the selected model's rated input and the controller output specification.
A change in diameter can also change the housing and mounting requirements. Check these details before substituting one size for another. Use the wiring checklist to collect the electrical information.
4. Separate modules, complete heads and accessories
State the supply scope in the enquiry. A replacement LED module, a housing and a complete signal head require different drawings and quotation details. List brackets, visors, connectors and spare parts individually where required.
Review the factory and packing photographs and 300mm module production photographs. For your order, request the applicable drawing, inspection scope and packing details.
Other sizes in the catalogue
For a project specifying another size, see the 100mm and compact signal range or the 400mm / 500mm range. Apply the same project, electrical and mechanical checks. Availability and configuration should be confirmed for the selected product.
Prepare a size-selection enquiry
- Required diameter, indication and number of sections.
- Complete head, replacement module or housing, with quantity.
- Rated supply and controller model or output details.
- Mounting drawing, existing label and replacement measurements where relevant.
- Destination, project requirements and requested delivery date.
Download the traffic light enquiry checklist to prepare your request.