G & R Technology Inc. Has been designing & building portable hardness testers for more than 20 years. Both the Rockwell Hardness Tester and the Leeb Hardness Tester are highly accurate, easy to use and suitable for testing a variety of materials. Our products are being sold in North America, Europe, Asia, South America and Australia.G & R Technology Inc. Was founded in 1992 in the state of New Jersey, USA, dedicated to designing and making high quality portable hardness testers.