We covered this #2 cold pack,so you can add it to your dogs' Zentek coat. Place it across the chest piece, to cool the dogs' chest area. this will keep the blood flow to the muscles, while still cooling the body core. It will fit most of the coats.( S4 to S7). no matter how old. We are using the soft velcro on the chest piece that is already there,adding the sticky side to the cold pack cover. if you have a S-1- S-3.. or an S-8 to S 10.. put in the order notes, the size. The S-1 to S-3 take a smaller pack.. and the larger needs a bigger pack cover... so just let us know, and we will adjust for you.