C.R. LAURENCE CAP38S CRL 1-1/2" Flush End Cap Screw Used with CAPF112BS. With the CAPF112BS Cap Assembly this 1-1/2" (38 mm) Cap Screw is used when the attachment to thicker panels is required. The CAP38S has 3/8"-16 threads and will work with CRL 1-1/2" and 2" diameter Standoff bases..