Astrodymium Colour Coded Spacer Rings for M42, M48, and M54 Threads

Description

These rings slip over the thread of an adapter/extension tube, and are primarily used for fine tuning backfocus when doing astrophotography, but they can be used for other purposes as well.
======================
M42 and M48 contain 12 individual spacer rings
, with 3 different thicknesses. 4 of each thickness is included: 0.4/0.6/1.0 mm.
M54 contains
9
individual spacer rings
, with 3 different thicknesses. 3 of each thickness is included: 0.4/0.6/1.0 mm.
======================
Each ring is also colour coded for easy identification.
Red - 0.4mm
Blue - 0.6mm
Black - 1.0mm
The width of the rings is 3.95 mm, and the inner diameter is 0.5mm larger than the specified size, for good clearance on the threads - They will not get stuck and are easy to insert or remove.
---
This product is made out of ABS plastic and can handle up to 75C (167F) temperatures without deformation.