Travel PAK (or zip pack) is a free gift from HIPER that you can use it as a travel pack. It's bundled with some of HIPER products and usually prepacked with some accessories such as cables and screws of the product.
Products that include travel PAK:
PSU: HPU-4S730, HPU-5K680, HPU-5B680, HPU-5K770, HPU-5K880, HPU-5B880
Chassis: HTC-1K614, HTC-1K514, HTC-1S514
Extender: HLC-2M1P-15, HLC-2M4S-15, HLC-3M3C-15, HLC-4M2E-15