tender for backing ring for ctrb, class e 6 x 11 (narrow jaw) drawing no. : wd-92089 - s-01, alt.-1,item no.9. spec. no. ab / rb - 39 - 2002 (rev. 4) guarantee : shall be guaranteed for satisfactoryperformance for a period of 48 months after supply or 36 months after putting into service whichever is later. (fordetails please see spec. no. ab / rb - 39 - 2002 (rev. 4) .