Specialty Products Company (SPC) 81134 Replacement Bubble for Magnetic Adjustable Camber Gauge (Part: 81139) Replacement bubble vial for Magnetic adjustable camber gauge. This gauge is inexpensive, portable, and very accurate. It has a simple leveling adjustment of ±3 degrees. Housed in a durable, nonmagnetic casing with a magnetic head that attaches firmly to rotors or spindles.