Description
The Seco Rear Locking 62 mm Premier Prism Assembly is a survey prism made by Seco (part number 6402-20-FOB / 6402-20-FLB / 6402-20-YLB (6×9 target); 6422-20-FOB / 6422-20-YLB (5.5×7 target)).
It can be set up in two positions, giving an absolute prism constant of 0.0 mm or -30.0 mm (+34.4 mm or +4.4 mm on the Leica scale). Always check which position is in use before measuring.
Specifications
| Model: | 6402-20 / 6422-20 |
| Manufacturer: | Seco |
| MPN: | 6402-20-FOB / 6402-20-FLB / 6402-20-YLB (6x9 target); 6422-20-FOB / 6422-20-YLB (5.5x7 target) |
| Status: | Current |
| Height Offset: | 115.0 mm |
| Absolute constant: | +0.00 mm or -30.00 mm |
| Leica constant: | +34.40 mm or +4.40 mm |
| Two mounting positions. Check which one is in use before measuring. | |
| Constant source: | Manufacturer documentation |
| Prism diameter: | 62 mm |
| Weight: | 790 g |
| Mount: | screw-in canister prism in tilting holder |
| Coating: | silver (product page); catalogue copy for rear-screw-lock Premier says copper |
| Housing: | O-ring sealed canister; stainless steel locking mechanism |
| Last verified: | 21/10/2026 |
Sources
Seco Rear Locking 62 mm Premier Prism Assembly FAQ
Below is a list of frequently asked questions about Seco Rear Locking 62 mm Premier Prism Assembly.
What is the prism constant for the Seco Rear Locking 62 mm Premier Prism Assembly?
The Seco Rear Locking 62 mm Premier Prism Assembly has two mounting positions. The absolute prism constant is 0.0mm or -30.0mm. The Leica constant is 34.4mm or 4.4mm.
Can I use the Seco Rear Locking 62 mm Premier Prism Assembly with a Leica instrument?
Yes, just set the prism constant to 34.4mm (or 4.4mm in the second position).
What is the height offset of the Seco Rear Locking 62 mm Premier Prism Assembly?
The height offset is 115.0mm.
