This Dead Air Replacement Wave Spring part for KEYMO and KEYMICRO Adapters is available for those of you who prefer to keep your own personal inventory of moving parts. This spring is the same part for all DA428 Keymo-HUB adapters, DA429 Keymo-Saker Adapters, DA451 Key-micro Adapters, It is also the spring that ships with all Sandman series and Sierra-5 KM.