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Amazon.com : Fotodiox Pro Lens Mount Adapter - M42 Screw Mount SLR Lens to Pentax K (PK) Mount SLR Camera Body & Replacement Rear Lens Cap Compatible with Pentax K Mount DSLR
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Pentax Mount Adapter K (M42 Screwmount to K Mount) Reviews - Pentax K-mount Teleconverters and Adapters - Pentax Lens Reviews & Lens Database