Dogtra 642C Training CollarThe 642C is an ultra compact system that packs all the features of larger Dogtra collars but is designed for small to medium sized dogs. Model for 2 dogs. Features Ultra compact receiver collar designed for smaller dogs Checkered grips on the handheld transmitter Nick and Constant stimulation along with the High Performance Pager Enhanced contact points Precise stimulation level (0 127) 600 meters range 2 hour rapid charge Lithium Polymer batteries