On sale one of the best multieffects for bass - ME-50B. Used also with guitars for low tunings (i used it with seven string guitar). Not many of them are on the market and they become a rarity . 
It has very big advantage - it operates like a chain of pedals in which You can easily change any setting . 99% of today multi-effects requires writing presets that are hard to modify without another writing... those which are the best sounding also require setting up the modelling amp... speaker... and sometimes even mic emulation. ME-50B is definitely more user-friendly despite having so much knobs (You will get use to it very quickly).
ME-50B is used by artists :
Ian Hill (Judas Priest)
Marco Hietala (Sinergy / Nightwish)
Jared Followill (Kings Of Leon)
Nikolai Fraiture (The Strokes)
Brett Campbell (Pallbearer)
Shabaka Hutchings (The Comes Is Coming)
Cat La Chapelle (Ventenner)

Since 2024 the ME-50b has been discontinued to make a room for the new but more expensive ME-90b. .
Mine piece works 100% but it has signs of use (like scratches) . Built like a tank . The adapter is NOT included . It needs standard 9V charging .