Older Mauser Spezial IWK rubber box which seems like it was probably a cleaning kit. I assume this is probably for a civilian rifle. The rubber is still pliable but there is some damage, like chunks knocked out on some of the thinner edges. I've had this for a while and have had no luck finding any information about it. I am fairly certain it is a rare Mauser accessory but I'm officially giving up on finding out what it is exactly.