Button, 1st Regt Sikh Infantry Punjab Irregular Force / 1st Regt Sikh Infantry Punjab Frontier Force / 1st Sikh Infantry 1861-1901. 
'1' in centre of Sikh quoit, 'SIKHS' inscribed on upper level, 'P.F.F.' on lower level.  Rim, blackened brass.  Reverse marked Hobson & Sons Lexington St London W.  
On a card of 45 buttons marked 11th Sikh Regiment, 12th F.F. Regiment, 13th F.F. Rifles from the Parkyn collection.