New Dog Fence Collar for Invisible Fence Brand Pet Fencing Systems - Better than the R21!| Invisible Fence System Frequency| 10k (Progressive) You Choose the Correction Level! Works on ICT 700,725,750,775,250,150,100,100A Transmitters NOT Compatible with Invisible Fence 800 Series Transmitters. Extremely Small & Lightweight Receiver Weighs in at Only 1.1 Ounces