Fruitland oil pump hollow bolt M-6 is designed for Beka Lube TDM style oil pumps. These are also know as banjo bolts. The bolts will fit several different Fruitland Vacuum Pumps RCF250, RCF370, RCF500, RCF870, RCF1200. The bolts hold the oil lines to the oil pump.
This is part #21 on the RCF370 pump exploded view and part #21 on the RCF500 pump exploded view.
The part number is 250-6