SE-14r light repeating blaster/Legends

The SE-14r, sometimes referred to as the Imperial repeating pistol, was an upgrade of the standard BlasTech Industries SE-14 blaster pistol, produced for Imperial officers, stormtroopers, pilots, and other crew. It was considered a backup weapon to the standard-issue E-11 blaster rifle.

Behind the scenes
The SE-14r is from publicity photos for A New Hope and not actually seen in any of the films, however, a similar blaster not in Imperial service, the SE-14C is seen being used by Dr. Evazan in the Mos Eisley cantina.

In the Battlefront video game series, the blaster is the Galactic Empire's sidearm.

For some reason the SE-14r is the standard Imperial infantry weapon in Star Wars: Empire At War and its expansion, being used by Stormtroopers in urban, forest, and temperate environments, and by Imperial Field Commanders and Scout Troopers in all environments, and is also out of scale, being roughly the same size as an E-11 Blaster Rifle despite it's blaster pistol status.