Both of the new flex control knobs are now available from Kirby Morgan. The combination of more grip edges and a slightly flexible polyurethane material, give these knobs an improved grip, while also providing increased impact resistance over the older, rigid control knobs, part numbers 520-016 and 520- 025. Severe impacts will be less likely to transfer to mating components. They are currently available as direct replacements for the old style knobs. There is no price change at this time. Part number 520-524 replaces part number 520-016 and part number 520-525 replaces part number 520-025.