FOR CLOSE ENDS
At Step 2, lower the BOWLS EYE so the Jack fills up the two inner circles before gauging the head.
FOR LONGER ENDS
Where the nearest bowl is further than 400mm (approx.) from the jack.
At Step 1, turn the BOWLS EYE 90* and instead hold the sides of the device, use the small circle at the end to gauge the distance.
Note – Using the device this way will give you a one-way view. Depending on where the two closest bowls are located, it may be necessary to line up the Jack to both bowls individually and compare results in order to assess the head.
Law 23.3 (part of): Examples of equipment or objects which, when used during an end, would not be deemed to be in breach of law 23.3 include cross-fingers and devices comprising concentric circles within a transparent frame which are held approximately waist high, and equipment or objects (such as a player’s foot) placed alongside or parallel to (but not directly between) the jack and the bowls.