A brown gripped Donnay Diamant from Bjorn Borg. This looks to be a later version of the black gripped Diamant. That one also has the extended grip area but with thicker stripped black leather as you can see in the other post. It was around this time that Borg had a special person assigned to his grips and started using Fairway leather.
This is a very rare racquet from the Lennart Bergelin collection. Impossible to find these anywhere other than on this site. this one shows some amazing use from several different matches and tournaments that Borg was competing in at the time. Nice photo reference of Borg using this same type racquet.