These bars were the first ‘empty’ item released by Casascius. They function like any physical Casascius coin in that bitcoin can be sent to it using the first-bits, but redeemed only by removing the hologram.
S2 2011 ‘Storage Bar’

These bars were the first ‘empty’ item released by Casascius. They function like any physical Casascius coin in that bitcoin can be sent to it using the first-bits, but redeemed only by removing the hologram.