Some convertible PC users sacrifice operating time for lighter weight, others are willing to accept extra weight if it means they can use the computer for longer periods. The Toughbook C1 achieves the best of both worlds by using a hot-swappable twin battery design. The Toughbook C1 comes standard with one battery and one weightsaver, but is available with two batteries. This design allows the user to choose between one or two batteries, for the ultimate in flexibility of weight vs. operation time. In addition, the ability to change a battery without having to turn the power off, means no downtime. Further, the Toughbook C1 is capable of rapidly charging both batteries at the same time — after one hour of charging, a single battery can power the unit for about 4.5 hours.