Well if the rubber cap that came on the tank counts then that would be it. However i don't consider that even close to this product.
Spyder pilot acs '05: 14" tru flight barrel
low rise clamping feed neck
dye sticky grips
run on HPA 72cc 3000psi
Even when taken off still attached to the tank
Have to disassemble tank to attach cord
This type of product is a must need for any one that uses a nitro tank. Dirty or debris can severly damage your tank. $5 to $10 is a small amount to pay to ensure the safety of your tank. Ok I am done preaching....on to this product. This is as simple as any dust cover. Secures to the fill nipple tightly. Has a cord to attach to the tank so that even when filling you won't lose it. You do have to remove a burst disc or the gauge or even the fill nipple to attach the cord. Please if you don't know what you're doing take it to a pro shop.
Over all solid product. A must have to protect your tank. Low price asorted colors. Really no reason to not have one.