The sICX / ICX pair serves a unique purpose: sICX represents a share of a pool of staked ICX, and therefore offers instant unstaking to sICX holders. It also does not follow the same pricing mechanism as other pools. It contains only ICX and charges a fixed 1% fee (adjustable via governance). Of this 1% fee, 30% is added to the network fee pool and 70% is received by the seller of ICX.