EXCHANGE REQUIRED Exhaust valve stem for Crosman 600 and 677. EXCHANGE INSTRUCTIONS: YOU MUST HAVE AN EXCHANGE TO PURCHASE THIS PART AND IT MUST BE IDENTICAL TO PICTURE OR DESCRIPTION. WE CANNOT SHIP YOUR ORDER UNTIL WE RECEIVE YOUR PART. PLACE YOUR ORDER, SEND YOUR UNDAMAGED PART VIA USPS ONLY, USING A PADDED ENVELOPE, TO JGAIRGUNS P.O. BOX 830, MUNDELEIN, IL 60060. INCLUDE ENOUGH POSTAGE. DO NOT INCLUDE ANY EXTRA PARTS, THEY WON’T BE RETURNED. DO NOT REQUIRE A SIGNATURE, IT WILL BE REFUSED. DO NOT SEND US TRACKING INFORMATION. IF YOU WANT TO KNOW WHEN IT ARRIVES, USE YOUR TRACKING INFORMATION BECAUSE YOU WILL NOT BE NOTIFIED. IF YOU ARE WORRIED ABOUT LOSS, PURCHASE INSURANCE, WE ARE NOT RESPONSIBLE.