This sale is for a mint condition Mamiya 645 Pro wrist strap, suitable for use on the Mamiya 645 Super, Pro and ProTL cameras – and the M645 series if you really want to.
This strap was originally sold with and designed to be used with a motor drive grip – and they certainly work extremely well in combination with a motor drive – I use one myself. This example has absolutely minimal signs of use, barely used.