Connecting tubes, Aluminium and stainless steel
GN 990-AL-D: aluminium, round section.
GN 990-NI-D: AISI 304 stainless steel, round section.
GN 990-AL-V: aluminium, square section.
GN 990-NI-V: AISI 304 stainless steel, square section.
Surface finish index:
BL: AISI 304 stainless steel natural finish.
EL: anodised aluminium, natural colour, matte finish.