You want small, we've got small. The 250 series is here! The right angle block has always been the workhorse of the Berkey System but in the case of the 250 series right angle block, it's more like a pony. These blocks are available in both a left and right hand version. Having a left and a right hand version allows access to the fastener even if you have two blocks side by side. An equal number of each is recommended. You can never have too many of these. Bore is .250 inch diameter. The fastener is a 6-32 and requires the 7/64th balldriver, sold separately.