This is a check retainer clip for the Ames 1000DCV series single check valve assemblies & 8-10" DCA/RP series devices. After removing the cover, simply slide the retainer tool into the holes in the side of the check. Unbolt the check assembly and remove the check with the retainer clip in place. The retainer clip may be taken out when the check is removed from the device. Use caution as the assembly will have spring tension.