Most CircuitMess products are kits — building them yourself is the point. A few arrive ready to use. Here is the whole picture in one place, so the box holds no surprises.
These arrive ready to use:
NASA Artemis Watch 2.0 — a fully assembled smartwatch. There is nothing to build; coding it is the optional second half. See NASA Artemis Watch 2.0 — Frequently Asked Questions.
Beep Boop — fully assembled and ready to play with straight out of the box. See CircuitMess Beep Boop — Frequently Asked Questions.
Butter Bot — both at once: the robot itself arrives assembled, and its controller and expansion modules are the do-it-yourself part. See CircuitMess Butter Bot — Frequently Asked Questions.
Everything else is a kit you assemble — Bit 2.0, ByteBoi 2.0, Chatter 2.0, Clockstar 2.0, Codee 2.0, Jay-D 2.0, Synthia 2.0, Wheelson 2.0, the Rimac Nevera and the NASA Mars Perseverance Rover. The effort varies a lot:
Nearly all of them need no soldering at all and go together with the screwdriver in the box — Jay-D 2.0 and Wheelson 2.0 among them — and Clockstar 2.0 takes about an hour.
Soldering comes into two of them: the Butter Bot's controller and expansion modules, and the Mars Rover — which is also the biggest build of all at around 20 hours — see NASA Mars Perseverance Rover: materials, power and where you can drive it.
Most product pages state the build time and recommended age, so it is worth a look before you buy. The recommended ages across the range are collected in Is there an age limit for using CircuitMess kits?
If you are choosing between building and wearing, the two watches make the contrast plain: Clockstar 2.0 is the watch you build, and the Artemis Watch 2.0 is the watch that arrives finished — Clockstar 2.0 or NASA Artemis Watch 2.0: which should I choose? compares them.