Caldercraft Model Boat Fittings 8103DN 3mm Double block. Natural.
Sold 1n packs of 10, these double blocks measure ((h) x (w) x (d)) 3.6mm x 2.9mm x 2.4mm and are available in natural boxwood.
Equivalent manufacturers part number cross references:
Artesania AL8519
Caldercraft 8103DN
Corel AMNB113
Mantua 37051
