Re-designed model but will still fit in previous model space without any alteration. Mounting on vertical bulkhead : Key Features Compatible with drilling Ø of former model same size Fits any bulkhead thickness :- standard thickness (40 mm max) : the compass is secured with threaded rods.- thick or double bulkhead : the compass is secured with Parker screws on both sides of the bulkhead. Excellent readability whatever the weather conditions and light. Conical, highly stable, 81-mm apparent diameter. Individually balanced. Graduation every 5° and compact figures for easy reading. 3 lubber lines for dependable readings even when steering windward. All parts fully UV-ray treated Scratch resistant dome. Techy Bits Boat Size : Sailboat up to 9 m ( 30ft ) Card : Red conical card, graduated every 5, apparent 81mm. Heading numerals every 30 Mounting : Flushmount on vertical bulkhead. On the mast ( with optional mast mounting kit ) Lubber lines : 3 lubber lines, at 45 Heelmeter : Graduated every 10 Compensation : Optional Lighting : LED 12-24 V Supplied with : Protective cover, drilling template, threaded rods. Homologation : ISO 613 compliant Height : 184.5mm Length : 134mm