Welcome to Nautos-usa !
The grey deck collar has an oval and tapered inner diameter. The oval inner diameter allows the maimum fore/aft play and minimum side play. The tapered inner diameter allows the mast to be raked. There are four countersunk mounting holes. Hole size in deck: 57mm. The EX12101 has a seperate sleeve which is fitted around the mast at deck level and protects the mast from wearing.
Optimist Bow Bumper
CORNER PROTECTION
Daggerboard Hold Optimist
Optimist Bailer
Bailer
Wind Indicator
Buoyancy Bag- Pillow Bag