Superior Labs 3 1/8" Cessna Mechanical Tachometer SL1010-43001-11-H02. Superior Labs (SLI) is the aircraft tachometer of choice by many OEM’s due to its precision and reliability. Superior Labs 3 1/8" Cessna Mechanical Tachometer SL1010-43001-11-H02. The Superior Labs 3 1/8" Cessna Mechanical Tachometer SL1010-43001-11-H02 has a Green ARC of 1900-2400, a Red Line of 2400 and records at 2300. SLI also offers precision aircraft tachometers for aftermarket replacement for most single engine aircraft. SLI manufactures aircraft tachometers for all general aviation aircraft types and offers custom screen printed dials, internal lighting, anti-glare glass, and pre-set engine hours. This specific unit replaces the Cessna S3329-1 Models.