These are intended to convert models on the lozenge hex bases from the 2007 Battletech Introductory Box Set or the 2012 Alpha Strike Lance Packs to full hex bases. They are scaled to fit models from the Lance Packs snugly however, due to the variability from production, you may need to trim and/or fill the bases for models from the Intro Box.

(In the picture, the Vindicator on the left is from the Intro Box, the Charger on the right from the Support Lance Pack.)