The Rolleiflex 4x4 Baby (prototype PR 205) is an experimental twin-lens reflex from Rollei, designed to shoot the 4x4cm square format on 127 roll film. As a factory prototype rather than a production model, it sits outside the regular Baby Rolleiflex lineage and exists in extremely small numbers.

Only a single UK auction record underpins this listing: one hammer result of £18,000 in November 2013, achieved at saleroom level before buyer's and seller's commission. With no comparable sales since, there is no meaningful range or median to quote, and any present-day value in 2026 would be set by negotiation between specialist collectors rather than by an active market. Prototype TLRs of this kind are highly condition- and provenance-sensitive, and what one sells for can vary widely depending on documentation.