I have a set of extra high, heavy duty matte black rings designed to be used as riser/rings on flat top AR-15 and .50 cal rifles. These rings are 30mm with 1" inserts and have heavy nuts which use a wrench to tighten onto a Weaver base or Picatinny rail. They are solid aluminum (not see thru) except for the nut and screw which are steel. $25 + $4.00 handling/shipping. For insurance add $1.30. I can send you a photo if you send me a PM with your email address.