Use this height adapter with Topcon 77mm prisms.
Height Adapter for Topcon 77 mm Prism
PN: 2090-01 Shipped From: 
Details
- 5/8 X 11 aluminum prism height adapters allow the base pole to be used with other manufacturer’s 360° Prisms
- For Topcon users with 77 mm prism
- Weighs 0.14 lb (0.06 kg)