- Protecting your products in transit or within your manufacturing processes is key to ensuring your products remain operational. At Essentra Components, we've got you covered, with our extensive range of Caps. In a whole range of materials from LDPE, PVC to Silicone, choose from sealing, quick fit, and valve caps to fit a variety of thread styles. Where there is a need for safe operation of hydraulic machinery, our hydraulic caps can help, such as Compression Fit, Side Release, Banjo Union and SAE Butt Weld Caps. Can't decide on which solution you need? View our range of guides and handy tips, A quick buyer's guide to Caps & Plugs and Design Engineer's Guide to Caps & Plugs selection.