The current commercially available Staafordshire flag is a single lion on a blue background atop a yellow flags with a red stripe featuring a knot.

The flag is actually quite attractive when flown such as here

The design appears to be taken from the County Coat of arms ,although the knot is white as shown on the coat of arms.

Flags of the World give the below definition of the County Crest: 

On a green field, the coat of arms of the county  on the chevron gules a Staffordshire Knot of the first on a chief azure a lion passant guardant of the field and for the crest issuant out of a mural crown proper a Stafford knot or as same are in the margin hereof more plainly depicted. And by the authority afore said I the said garter do these presents grant and assign the supporters following that is to say on the dexter side a lion reguardant gules crowned with a ducal coronet or and on the sinister side a Gryphon reguardant or as the same are also in the margin hereof more plainly depicted the whole to be borne and used for hereafter by the Stafford county.