Sportdog two collar system, Amazon price $248. This set was purchased as one collar initially and then as a second collar. was added for another dog. One control is programmable for two dogs simultaneously. All manuals and spare batteries (1 collar, 1 controller) included. One collar has 21 levels of control and 2nd collar has 14. Each collar has tone only or tone and shock. both have number control for shock as either low or medium while the 21 level collar has low, medium or high shock. Shock buttons have instantaneous less than a second and the other for 5-6 seconds duration which I never needed to use. Test devices included to determine if shock function is working.