The Dogtra SureStim 7100H has a 1/2 mile range and is a low to high-range power training collar with higher stimulation levels for stubborn dogs, It offers continuous and momentary stimulation, plus non-stimulating vibration, The switchable ""SureStim"" feature lets you know for sure that you have pressed a stimulation or pager button through a positive feedback vibration in the handheld transmitter, (Sure Stim can be deactivated to preserve transmitter battery life, ) The rheostat dial gives you smooth adjustment without jumps from one stimulation level to the next, SKU: GVDS1004