The CipherLab PST-RS38 detachable pistol grip (ARS38PSTNNN11) is an accessory for the RS38 series. Its pistol-grip form provides a different way to hold the handheld device during use.
This part is detachable, so it can be removed from the device. It is specified for use with a rubber boot; the listing describes it as suitable for the RS38 series.
The product is identified by part number ARS38PSTNNN11. The rubber boot is a required part of the described setup.