Multi-Shank Layout
Several shanks on one probe, so the array samples a plane rather than a line.
Two-dimensional coverage. Shank spacing and site spacing are both specified, so the array covers an area of tissue instead of a single track — a more detailed picture of a larger space than one shank can give.
The layouts compose: a multi-shank design may carry tetrode or polytrode groups on each shank, putting unit isolation and 2D coverage in the same probe.
In a model number the leading field is shanks by groups per shank — the 4x8 in A4x8-tet-5mm-100-200-177. What a "group" is depends on the layout token that follows, so the figure does not resolve to a site count on its own: a2x2_tet carries 4 sites and a2x2_tet_3mm_150_150_121 carries 16, on the same leading field. Read the site count from the specification, never from the name — across the A-Series tetrode designs, "sites per shank" is the correct reading on 16 records and the wrong one on 44.