Grex A150018 - Air valve assembly Grex from $11.73 $14.30 Qty. Add to Cart SKU: GRX-A150018 This item is currently on backorder but you can still purchase it now and we'll ship as soon as more become available. Genuine Grex replacement part A150018 - Air valve assembly. For Grex Models XT, TG, TS. Chart referance number 24. Tweet