Silva Map Measurer

I have just bought myself a Silva map measurer. I will now be able to measure distances on my map accurately. The measurer measures in a range of different scales, eight in fact. 1:750k, 1:500K, 1:400K, 1:200K, 1:100K, 1:50K, 1:25K, 1:15K.

I would normally use a 1:25K so this should work out just fine.