If you’re getting a Fischer boot for the unique properties of its Vacuum Fit, namely the ability to shrink-wrap the shell around the foot, then it only makes sense to start with the narrowest shell you can slide into. This makes the RC4 series of race boots the models of choice to optimize Vacuum Full Fit. Because Vacuum Full Fit also allows for shell expansion, even if the shell impinges a bit out of the box, going tight turns out all right in the heat-molding game.
The narrow, 98mm last of the RC4 comes in a no-wimps-need-apply 140 flex, a still plenty sturdy 130 and a more pliable 110 flex, which brings this unique and useful technology into the wheelhouse flex range for the weekend warrior. We cannot overemphasize the importance of accurately matching the contours of a semi-rigid, supportive shell around the lower leg, ankle and mid-foot. This is what the Fischer Full Fit Vacuum technology in the RC4 last is designed to deliver, and in the hands of skilled bootfitter, deliver it does.