Standard fasteners are easy to open. but SAIMA TRF has many varieties, so it is difficult to open without special tool.   If you want to add an aspect of security, SAIMA’s TRF is one of the best choices. SAIMA is doing TRF business from 1998. We receive many project of security and help customers. If you are really interested in security, please not hesitate to ask. SAIMA TRF Page https://www.saima.co.jp/en/Product/trf/top.php