Psion Art.No.: RV6005 "Cable charging 1.5m usb(a male) handilink (used with rv1000)", P/N: 1101044 - former Art.No. RV6008 (very same product).
This cable will be plugged in the docking port of the EP10 and allows to connect a mains power adapter. You can charge now the EP10 directly with a power adapter (PS1050 or RV3050). This is a solution where charging with a docking cradle is not possible (outdoor etc.).
Mainly it is intended for use inside vehicle to charge EP10 unit with vehicle power adapter RV3050.