Marked "Pat Apld For" high on the face and "Adjustable Putter, Pat Apld For" on the sole" this club was eventually covered under a US patent issued to Edwin C. Allen on March 11, 1924.  The brass hosel on the club can be adjusted so the club can be used as a putter or chipper both right- and left-handed as well as croquet style.  The base of the hosel is threaded so that it can tighten, loosen, and pivot back and forth across the top of the head.

What appears to be the back of the head is a dual face, with a lofted lower portion and vertical upper portion.  The loft lifts the ball while the vertical propels the ball forward when struck.  Overall, Allen's adjustable is very similar to James Boye's adjustable putter/dual-face chipper patented in the US in 1922.

This club is in working condition.  The brass hosel is thinner than was normally used on a wood shaft club and that is because the hosel was made for a steel shaft.  An Allan with a larger, wood-shafted hosel is shown in TCA2 volume 2 page 464.  This club offered here, however, was likely reshafted with a wood shaft years ago and remains a very handsome club.

This club is the top club in the group image that accompanies this lot.