http://www.surmaq.com/html/cata/parker/contr/skinner.pdf[永久失效連結] pp. 128-131; tech details of design; different terminology; welded sleeve; valve sizing. Page 128: "Skinner Valve plunger assemblies, when appropriate, use floating top and bottom seals to enhance valve performance. Floating seals permit the plunger to generate a larger actuation force to open against the pressure differential in the valve. This enables the valve to operate at higher pressure ratings." Material has implications for shading ring: copper is satisfactory for many materials, but it is unsatisfactory for coffee and urea; silver is satisfactory for those fluids. (pp 130–131.)