Astrodymium Fine Adjustment Spacer Rings for M42/M48, and M54 Threads

AstrodymiumSKU: M42-SPACER-RING

Size: M42 (16x)
Sale price$12.99
In stock


These rings slip over the thread of an adapter/extension tube and are primarily used for fine tuning backfocus for astrophotography, but they can be used for other purposes as well.

Also available on Agena Astro (United States) and First Light Optics (UK / Europe)!


M42 comes with 16 individual spacer rings. 4 of each thickness is included: 0.4/0.6/0.8/1.0 mm.

M48 comes with 12 individual spacer rings. 3 of each thickness is included: 0.4/0.6/0.8/1.0 mm.

M54 comes with 9 individual spacer rings. 3 of each thickness is included: 0.4/0.6/1.0 mm.


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). 


Made out of UV resistant PETG plastic that can handle up to 80C (176F) temperatures without deformation.

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Customer Reviews

Based on 1 review

Fits exactly as needed! Will be buying from here again.

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