Hobbypark 4pcs RC Airplane Prop Saver 3.17mm with Screws Rubber O Rings Kit for Electric Engine Brushless Motor Shaft E Plane Replacement Parts

Works great saves on buying props

For larger props at high RPM this wobbles a bit too much for my liking but overall it works as advertised and id recommend them if you know their limits.

Prior to getting these, as a newbie to RC, i broke at least 2 propellers every time I went to the field to fly my planes. Went to the field with these on my planes, and came back home with the same number of props I went out with.

Couldn't return. Be sure to mic the shaft on your motor before purchase.

Worked well for what I needed. The o-rings break a lot so it would have been nice to get more, but I was able to purchase more for pretty cheap at the hardware store.

The orings are not very good. The adapters work great but I use a big rubber band and longer screws with it.

Work as expected. Saves your prop and motor from possible damage.

Good thickness

One of the 4 had a less than 3.17mm bore, and was nearly impossible to get back off