Fender Callus Builder (891922002223) Building Calluses is essential for playing a stringed instrument Over 2 million new people start playing a stringed instrument each year. Twelve months later, 90% stop. The number one reason for stopping is pain from lack of calluses and finger strength. We designed the Fender Callus Builder and Finger Strengthener to help in both these areas. Easily simulate the exact angle you play your instrument Unlike most finger exercisers, the Fender Callus Builder can be held at different angles, allowing the user to exercise at the same angle that they play their instrument. What Strength is Right for Me? The Fender Callus Builder is available at two tensions, Red=8-lbs and Black=15-lbs. These tensions were measured by a force gauge applied between the first and second outer raised edges. If you move your fingers closer to the center, the tension increases. For example, if the User applies pressure between the third and fourth raised edges, the tension will be 50% higher. We are not aware of any other finger exerciser offering 15-lbs of tension, as well as the flexibility to increase the tensions to over 20-lbs by simply moving your fingers closer to the center. For beginners, the Red Perfect Pinch will suffice. As you strengthen and improve, it will be time for the Black Perfect Pinch. For experienced Musicians, and Bass players, you will want the Black Fender Callus Builder. We do offer a combo package at a discounted. FENDER ? The World?s Best Musical Instrument Manufacturer has teamed with the World?s Best Callus Builder and Finger Strengthener to bring Musicians the best licensed product to help Musicians enhance their playing experience. Designed in the shape of Fender?s World Famous Stratocaster Guitar. RAISED RIDGES ? The only Finger Exerciser with raised ridges to simulate strings on your stringed instrument. HELPS BUILD FINGER CALLUSES - A callus is an area of thickened skin that forms as a response to repeated friction, pressure, or other irritation. The Fender Callus Builder is designed to create pressure similar to the strings on a stringed instrument. SIMULATE EXACT ANGLE FOR PLAYING ? It is easy to maneuver the Fender Callus Builder to get the exact angle used while playing your stringed instrument. HIGH TENSION - Two different resistant levels available, RED 8-lb and BLACK 15-lb. The 15-lb tension is extremely hard and offers a higher tension than any other finger exerciser on the market.