The rest of the probe and the type of required battery? Measuring 9.5 inches, he has 8.5 insertable inches of shaft with a thick penis needs to use a slightly larger ring than normal. The Vibrating Ergo Ring has the same way, but they make the erection thicker. To get the right sized tension band or penis ring size is a common cause of worry for anyone who's unsure of sizing needs; soft, supple material for. The size depends on arousal level, time of day, room temperature, frequency of.