-6 or -8 is typical for 80A Enderle or small Hilborn, Waterman or DSR fuel pumps. -8 thru -12 fits 110 thru 1380 Enderle, Waterman, Rage, Hilborn, Settles fuel pumps. O-rings and Teflon seal is designed to withstand the abuse of gas, alcohol or nitromethane.
These shut offs should only be used for an application such as a high low valve or to shut off fuel from a tank but not on the fuel pump as dead heading the fuel pump can cause fuel pump damage.