In summary, Schroff offers a variety of PCB retainers from economical card guides to high performance card and wedge loks. The primary purpose of a Card or Wedge lok is card retention, and a secondary benefit is thermal transfer via conduction. Within the Schroff lineup, Card Guides and PCB Tainers are most suitable for static electronics in laboratory and commercial applications. At the other end of the spectrum, card and wedge loks are ideal for high shock and vibration rugged environments often found in military and defense, oil and gas, or subsea applications. The first step to determine which product to use is to know whether it is a sheet metal or cold wall installation. Card Guides, PCB Tainers, and Lever Lok Tainers are used primarily in sheet metal applications and Wedge Loks are used in cold wall applications. Unlike traditional card and wedge loks, the torque limiting card lok is unique because it does not require a calibrated torque wrench for installation. The patented torque mechanism is built in to simplify installation and provide consistently repeatable, optimal, and reliable results. When a Card or Wedge Lok does not provide adequate board retention or thermal transfer, Heat Frame and Conduction Cooled Assemblies can be used in conjunction to improve performance.