It's a very good couplerIt is solid unit and is 5mm to 4mm, spot on.Adaptateur de remplacement pour Princess v-hull. Parfait.Well trimmed and precise adapter, good quality, fully functional, tested it with the engine 3660SL 3180kv Brushless inrunner.Very nice adapter well made,
I ran my motor without this adapter and no vibrations, then I fitted it on also no vibrations conclusion it must run true. You have to tighten the flexishaft nut very,well it tends to slip under high power because it has no bras insert.Never received motor had to open paypal claim to get money back hk never replayed to my emails what a joke customer service think twice before you buy anything here in the end paypal refund me my money as u see hk did not want to do that! !!!Otimo produto! Recomendo a compra!!!Super quality i want buy other 10 pcs thanks hobbyking !recive today and real nice piace and decription its ok motor is 5mm and shaft is 4mm??????????????????????????????