SCOTT GAS MASSK w/ NETTED HARNESS---SIZE UNSURE shops 5

Product Name: SCOTT GAS MASSK w/ NETTED HARNESS---SIZE UNSURE shops 5
This is a Scott Gas Massk with a netted harness that has stretchy elastic straps.........It's shops a bit dusty and could used some cleanup but it's not dirty or dry rotted at all!........it smells like clean newish rubber on the inside........The inner rim of the rubber seal that wraps around your face inside measures 5” at it's widest and about 6 ½' from the top rim to the chin.........It seems that it is missing something but I don't know anything about these really.................With that said, be your own expert by reviewing my pictures and ask questions before purchase if you have any additional concerns........OTHERWISE THIS IS AN AS IS SALE WITH NO RETURNS.