The text is:

СТАЛКЕР
ЖИТЕЛИ ЗОНЫ

which means ‘Stalker. Inhabitants of the Zone’.

The letter ‘з’ is written inaccurately on the patch. It looks more like ‘ә’ or ‘э’, but I think the word implied is ‘зоны’. I’m not really into the Stalker games or Strugatskys’ fiction though. Please correct me if I’m not right.