The Wilco Probe 'N Funnel is not hollow, it is just used to make holes. When using you would take out the probe, then insert the included baiting funnel and then with or without the extended spoon add the bait to the funnel to go into the hole.
Wilco Probe 'N Funnel 70300 can be used with baits that are short and long grain carriers are perfect for this probe like the Kaput.
Wilco Probe 'N Funnel 70300 is made of both metal and plastic. The probe and measuring spoon are metal. The funnel is plastic.