adidas UltraBoost 21 "Grey Sonic Ink"
The adidas UltraBoost 21 "Grey Sonic Ink" (S23871) released Tuesday, August 31, 2021.
Original retail (2021): $180 · Lowest resale ask: $103 on Flight Club (Nov 14, 2026)
Colorway: Grey Five/Core Black/Screaming Green · Style code: S23871 · Release date: August 31, 2021 · Lowest resale ask: $103 · Availability: Available now
Source: GOAT's catalog · stores checked Nov 14, 2026, 4:21 PM ET
More colorways & related: adidas UltraBoost 21 "Black Iridescent" · adidas UltraBoost 21 "Triple Black" · adidas UltraBoost 21 GORE-TEX "White Sonic Ink" · adidas Adizero F50 SP5DER "Supplier Colour" · adidas Adizero F50 SP5DER — Solar Green · adidas Kader · adidas x Rick Owens Springblade Runner · adidas x Rick Owens Sprinblade Boots · adidas x Rick Owens Runner · adidas Formotion F50 · adidas Formotion F50 · adidas Anthony Edwards 3 — Lucid Pink