I have never been able to get past the looks of that trike. It just screams 'entry level'. Cheap, if I'm being mean. Don't do it. There is a trike called the ''Gekko". It might be an HPV model, maybe AZUB but it's deffo European. I was gobsmacked at how ... inexpensive it was. I would pay twice what they are asking, and I'm not a trike type. If I had to lock that Trident(?) I would find a way to get the main tube next to something that will fit in an 11" U-Lock AND get one of those tamper alarms. A Gekko and anything nicer I simply would not leave unattended. I would not. Someone committed to using a trike as a car replacement simply has to think outside of the box with respect to security. There are motorcycle chains that surely must be up to keeping a trike safe if they keep $14K super bikes off of Craigslist. Or just go to ACE Hardware and get 3' of a thickness of chain that you think suffices. Ask them for a suitable padlock. Bob's your uncle.