Netted Wrap N Go Harness X-Small 	7" to 9" neck 	9" to 12" chest; Small 	9" to 12" neck	12" to 15" chest; Medium 	12" to 15" neck	15" to 18" chest Large 	15" to 18" neck 	18" to 22" chest; X-Large 	17" to 21" neck	22" to 27" chest.