Features: 1) 6mm or 8mm thickness 2) Made of high quality CNC machined aluminum 3) Direct fit standard TRX-4 4) 3 color for select Source Samix: 6MM https://www.rcsamix.com/index.php/feature/trx4-6063-6-trx-4-alum-hex-adapter-6mm.html 8MM https://www.rcsamix.com/index.php/feature/trx4-6063-8-trx-4-alum-hex-adapter-8mm.html