Comparison : Item # RNRW1604MO, Round Negative with ISO Style Hole, thickness 0.198 / 0.206 in
Item # RNRW1605MO, Round Negative with ISO Style Hole, thickness 0.228 / 0.236 in
Item # RNRW21.5, Round Negative with ISO Style Hole, thickness 0.105 / 0.111 in
Item # RNRW22, Round Negative with ISO Style Hole, thickness 0.135 / 0.143 in
Item # RNRW32.5, Round Negative with ISO Style Hole, thickness 0.166 / 0.174 in