This is HPI’s (#75194) newest center shock. It is the lightest and also has the least amount of piston slop compared to the other center shocks.  The e-clips hold the piston securely. The latest version has a few new design improvements. Instead of a double O-ring seal, they now use a single O-ring in combination with a plastic retainer. This helps to reduce the friction on the shaft while retaining a superb seal. Those components are now encased by a new housing that makes it easy to assemble or perform maintenance. The shock cap has also been redesigned with edges to provide a better grip. The shock still used the bladder for the ultimate in consistency. The shock is made out of 7075 aircraft aluminum.