This meter has not been tested. Sold as is. The Vintage Sears Penske No. 244.21013 Dwell Tachometer is a classic tool for analyzing and measuring RPM and dwell, perfect for motorcycle, passenger vehicle, and heavy-duty/commercial vehicles. With its analog display and vintage appeal, this dwell tachometer is a unique addition to any automotive diagnostic tool collection. Made by Penske in the United States, this product includes clamps for easy installation and provides accurate readings for engine monitoring. While this item is not tested, it holds potential for those looking to add a piece of automotive history to their toolbox.