The brands we carry at High Point Scientific. The manufacturers listed at any given time during your search refinement offer at least one product that matches other search criteria you have already chosen.
We have hundreds of adapters & spacers, so filtering by a range of sizes was in order. Use this filter if you are looking for a particular length. For instance, if you want a 25 mm extension, then click the 20.1 mm - 30 mm box. Once you get those results, you can filter further by barrel size, thread type, etc.