These are a direct replacement for the original steel retainers all 2 valve air cooled Kawasaki:
Z900
Z1000
GPZ1100
 
4 x Intake + 4 x Exhaust

Made of best grade titanium - Grade 5.

The original retainers weight 16,2g and the titanium retainers weight 9,1g, 45% lighter.

These retainers have a smaller profile/height (shorter by 0,5mm) to allow for more valve lift without contact with oil seal and without requiring valve guide modifications.

Using lightweight titanium retainers allows for more aggressive camshaft profiles (lift and duration) without losing control of the valve and increased rpm limits - a must for any performance / race engine.