Keystone is a family business with over 65 years of proven manufacturing and composite material fabrication experience in the oilfield industry.Since 1950 Keystone Engineering Company has maintained a proven reputation for reliable products in the oilfield industry. Product experience includes the manufacture and production of formation measurement instrument assemblies for wireline, MWD, and LWD; and the manufacture and production of high-temperature, 400° F (204° C), composite bridge plugs. -drawings-financial documents-personal information of employees-quickbook backups http://keystoneeng.com