The RX-090 can be a replacement receiver or for adding another dog onto your current transmitter(remote). You have the option of buying this as is or with a collar strap. Please contact me before purchasing so that we can make sure this is the right receiver for the transmitter you have. 
 
There are 2 other receiver types E-Collar Technologies makes, and I can order that for you if needed.
 
The RX-090 is compatible with the ET-300 and EZ-900 models.