The Hamilton Auto Cal Delta in stainless steel was only produced in 1973 and was not listed in publicly available catalogs, making this a relatively rare watch. The orange dial is VERY hard to find as well. Low production, and low public visibility makes this watch hard to come by. It has a period correct origional Hamilton Bracelet.
Running on point.
Caliber 681
1973 Rare Hamilton "Delta" Automatic watch Origional Hamilton Band