Wraith handblasters are hand held versions of the Wraith stunner. They are typically carried by commanders, though they have occasionally been used by the lower caste of Wraith warriors. The Atlantis expedition has managed to acquired some of them and often use them if they want to capture an enemy alive.
The Wraith handblasters are handy little weapons, being capable of stunning most humans with one shot. Even though most humans get incapacitated for some time after a single shot, strong humans who have experienced the effect of the stunner on several occasions are usually more resilient. Ronon Dex, being an extreme case, has been able to withstand three blasts before going down, and the effect don't last very long on him. The Runner Kiryk was also resilient. Wraiths usually need two blasts to become incapacitated.
Humans pumped up on the wraith enzyme, such as Lt. Aiden Ford, are virtually immune to the stunners as long as the level of enzyme in their body are high. The stunner blast had little to no effect on Lt. Colonel John Sheppard when he was turning into an Iratus bug/human hybrid. Ronon's particle magnum could stun him, however. (ATL: "The Siege, Part 2", "The Siege, Part 3", "Allies")