Wattz Electronics THT Tapes are the standard re-recordable media for the 21st century. The standard THT tape holds 64k, while larger tapes can hold as much as 264k work of data. THT Tapes, commonly called holodisks, use Tape Holography Technology to store their information safely for years, and can be used in most compatible readers (such as all models of the RobCo Pip-Boy starting with the 2000 series). High-density crystal holodisks were also developed, but saw little commercial success due to the lack of rerecordability. These models were used by governments and the military and could hold as much as 4,000g of data. Weigh 1 lbs. (standard), or 4lbs. (high-density).