The OTs-28 is a prototype Russian shotgun.
The OTs-28 was developed alongside the KS-23K shotgun. The OTs-28 turned out to be more expensive to produce than the KS-23, and was rejected in favor of the KS-23K. As a result, the OTs-28 was never adopted.
The weapon is a pump-action weapon fed from a 5-round box magazine.