On either side of the LM-RondoPlus there are LM-Fingo test sticks. Sharpness can be tested both with Fingo mounted on the LM-RondoPlus or your finger. The Fingo is made of an acrylic plastic and is sized to fit all users.
LM-Fingo is included in the LM-RondoPlus package (LM 8600). It’s also available as a spare part and can be ordered separately in 2 pcs (LM 8602) package or 6 pcs package (LM 8606).