The Ark--A Medigun

The Ark
Level 20 Medigun

Allows you to select two heal targets simultaneously.
50% Healing during dual-heal

Ubercharge: Arcing Bolt Wall

Upon an ubercharge, healing speed returns to normal and both patients earn an 85x50 HU wall of invulnerability that centers on their crosshair. Enemy fire cannot pass through the wall, but enemies themselves can. If the two patients stand within 200HU of one another, their walls will arc together, becoming a single long wall 300HU wide. Projectiles vanish upon hitting the wall, but players will absorb knockback force as normal.

50% healing means that both patients receive 50% of their normal healing allotment. If you're healing one patient (A) who has 100% rampup and one with 0% rampup (B), A would receive 36HPPS, while B would receive 12HPPS. "Double healing" during the ubercharge means that healing returns to its standard amount