The INNOVA 3612 Compression Tester 4 Piece Kit is designed for automotive diagnostic service tools, specifically for testing compression and vacuum levels in engines. This kit includes a compression tester with a 2-1/2-inch dial gauge, a 15-inch rubber hose, and 14mm and 18mm thread adapters for compatibility with a variety of spark plug types. The INNOVA brand is known for producing high-quality automotive tools, making this kit a reliable option for mechanics and car enthusiasts looking to accurately diagnose engine performance issues.