Each of these hardwood lever grips is about 5" (130mm) long, and serve to increase the effective length of the lever by about 2 1/2" (65mm), so the lever arms are about a total of about 10 1/2" (270mm).
We originally designed these in response to a request to make the levers easier to push down when pulling a shot... Physics and logic indicates this would be the case - more force from a longer lever. We don't have the Barista model with pressure gauge, but we can make this observation: with the non-Barista model, one basically relies on muscle memory in pulling the shots, and with no changes in our workflow, or coffee, but basically using the same force on the levers, it doesn't feel 'easier' to push the levers down, but the espresso seems better.... Higher pressure, with the same effort? Confirmation bias? We don't know.... maybe higher pressure is the answer to why.
These grips are one of the 'Robot Changer' accessories. The UI (User Interface) just feels different, more like a good old Lever Machine, which we love! This is a bit similar to the wooden Portafilter Handle cover - it just feels nice! When pulling the shot, particularly pre-infusion, you can simply lay your hands across the grips to maintain a low pressure, then for the pull, slide out to the end of the grips. Most enjoyable to be able to move your hands - with the original hands, Mittens, or Woodies, you tend to keep your hands in one place, not altering your grip at all.
One caveat - due to the way the original cast stainless steel arms are manufactured, the 'wrists' and 'forearms' are not all exactly the same dimension. On our Robot the left forearm is bigger by a tiny bit than the right forearm. We think the hands are pretty uniform. On ours, we used a wrap of blue painter's tape to take out the tiny bit of wiggle in the lever grip - no tape was needed on the left set. So, YOU may need to adjust yours with a bit of tape to fix a wiggle! We only have one Robot to test, you may have a forearm that is exceptionally fat...if that's the case, and you're motivated to use these grips, we'll work to accommodate your machine - just let us know!
Assembly bolts (included) match the head on the top of the Robot, and we include a 4mm Allen key for installation.
Made from American Black Walnut, or Red Oak, in our workshop in Idaho, USA.