Casio MT-31
This little plastic thingy is actually one of the veterans in SHotQs
studio. Purchased by the young Carlberg in 1982 at the price of 1000 SEK,
it was to be an extra sound bank to the keyboard playing lad's "main
axe" - a 
Yamaha PS-20 "Portasound"
home keyboard. The latter is long gone, but the Casio is still going strong!
What then makes this simple instrument worthy of a place in SHotQs arsenal? The 22 sounds are not very exciting (despite odd inventions such as "Synth Fuzz" and "Oriental Pipe" and a brass sound that is rather good). The small keys, stained and sticky after too many spilled tour drinks are hardly stimulating either, and the performance controls are limited to vibrato and "sustain" (release) on/off.
Well, apart from pure sentimental reasons, there are a couple of things going for the MT-31:
1) It's very small and portable.
2) It runs off batteries.
3) It is eight note polyphonic, something rarely found on budget keyboards of later years.
Furthermore, for a long time it was equipped with a sling-on strap made from gaffer tape, the length of which was adjusted so that the instrument covered the genital regions of the player. Perfect for those nude gigs on Ibiza!
That's probably it! SHotQ have used the Casio here and there on different songs, but it's best heard in the vocal chorus of "Trickeration", where it is the sole player, more or less.