4mm ID THREADED PRECISION RINGS for APC E

These are precision machined from hard aluminum to insure a wobble-free, perfect fit of APC E props to THREADED 4mm gearbox shafts, such as found in GWS-EPS400, HYPERION HP-XG-400, and some other brands. These are really necessary, as the stock APC 4mm precision ring isn't tight enough on threaded shafts to give a good center to the prop.