Vernier sells four different types of Heart Rate Sensors. Two of these sensors, the Go Wireless Heart Rate and the Hand Grip Heart Rate Sensor use Hand Grips. The Hand Grips have snaps that accept a Polar Transmitter Module. Hand grips that were sold before July 2020 came with a Polar H7 Module. These hand grips can only be used with the H7 module. Hand grips that were sold after this period have been modified to accept H7, H9 or H10 polar modules.
You can tell if you have older or newer Hand Grips by examining the area of the grips that accept the module. If the area between the snaps contains a square-like depression, it is the older set of Hand Grips. You should also be able to see that the snaps are just slightly raised from the mold. The newer Hand Grips do not have the same depression and the snaps are also clearly raised from the mold. Please see the images below. An arrow has been placed to identify the region of Hand Grips that are significantly different.