This elastomer coupling spider joins two series 12 half-couplings. See the "Compatible Products" tab for a complete list of compatible couplings.
Jaw couplings are designed to connect to other jaws in the same series, which gives you the option of coupling two differently sized shafts together. Between the two jaw couplings, the coupling spider is used to hold them in place while still allowing for a small amount of flex. The jaw couplings in the list below will fit together with this spider: