I seem to recall it just pushes in. Purpose designed to drop in the tank so you get to use the special laser etched with a naked photo of Ewan Mcgregor, logo'd, forty quid, bit of chewing gum on a stick to fish it out and impress all your mates who only got the laser etched with a naked photo of Charlie Boreman, logo'd, thirty-seven quid, bit of tea strainer that pushes in the tank.

Send it back and buy something that comes filled with nice cheap wine, creosote substitute or even fabric softner.
Andy