Review on Beduan Reducing Fitting Reducer Splicer Hydraulics, Pneumatics & Plumbing by Adam Tidd

Purchased to eliminate the pipe fitting. I currently have two hose adapters screwed together. I can't use them for fuel lines on my boat as they violate USCG 183.558 as the smaller outside diameter on the 5/16 end is over 20 thousandths smaller than the inside diameter of the 5/16 hose. Connectors): 3/8 OD: .401 (.433) 3/8 Small OD: .363 (.384) 3/8 Barb Length: .707 (.937) 5/16 Large OD: .315 (.356) 5/16 Small OD: .291 ( .317)5/16 tooth length: .685 (.966)