overall: 4 1/2 in x 13 in x 9 in; 11.43 cm x 33.02 cm x 22.86 cm
Edwin A. Link, Jr. presented this bubble sextant, in a beautiful alligator case, to P. V. H. Weems. It is a standard A-12 with an attachment that enables the user to view the real horizon. Link applied for a patent on this feature in 1943.
Ref: <i>Link Bubble Sextant (Octant) Model A-12 Handbook: Description, Operation, Use, Adjustment</i> (Binghamton, N.Y.: Link Aviation Devices, Inc., 1943).
Edwin A. Link, Jr., "Navigation Instrument Including a Horizon Attachment," U.S. patent #2,395,559