STDC-105 - 

Round Shape, For Use with MX-DS1 pistol grip desolder handpiece, Solder Tip

SmartHeat Technology
Metcal improves product quality, increases productivity and reduces manufacturing costs with its patented SmartHeat technology. As SmartHeat maintains a constant tip temperature, automatically delivering the exact amount of power required for the task, consistent results are guaranteed and component/PCB damage is virtually eliminated. Metcal's SmartHeat systems offer task-specific versatility with no limits, no barriers and absolutely no compromise.
Highly durable and designed for high heat transfer, making desoldering on multi-layer boards much easier.