These are a quality prop adaptor with grub screw attachment to the motor or gearbox shaft; they provide an elegant alternative to the standard prop adaptors which are best housed in a spinner. Two sizes are currently available:
Fits shaft size
Bore of adaptor shaft
Price
4mm
8mm
$14.50
5mm
8mm
$16.50
Heavy duty prop adaptor - Graupner also have a very solid collet type prop adaptor with a long shaft, without dome nut:
6mm
10mm
$18.95
Himark prop adaptors - domed nut:
These are smaller adaptors (collet type) for a neat finish to the front of your smaller models -available for 4mm or 5mm shafts at an economy price - because the adaptor shaft is turned down to 6mm they will fit APC-E props without adjustment.