User manual Head BIS M-300-001-S1156 Edition 07/03 not flush mounting General installation notes for BIS M All read/write distances presume ambient temperature +20°C It BIS M components are mounted Tn or on steel , or there is metal within the active field of the recd/write heed , the field fete will be reduced and communication may be compromised. When ‘stalling data carriers on or in steel , note the reduced read/write distances. Precise distance data available on request.