▁We ap on ▁Fire ▁Unit ▁( WF U ) ▁version ▁la cks ▁the ▁cent r ally - mount ed ▁rad ar ▁but ▁can ▁be ▁cu ed ▁and ▁directed ▁by ▁the ▁fire - control ▁rad ar ▁of ▁the ▁former . ▁This ▁Singapore - mod ified ▁version ▁of ▁the ▁M 1 1 3 ▁is ▁field ed ▁by ▁the ▁Republic ▁of ▁Singapore ▁Air ▁Force ▁( RS AF ) ▁for ▁use ▁in ▁ground - based ▁air ▁defence . ▁ ▁South ▁Vietnam ▁ ▁M 1 1 3 ▁w / ▁M 8 ▁tur ret ▁- ▁The ▁Army ▁of ▁the ▁Republic ▁of ▁Vietnam ▁( AR V N ; ▁South ▁Vietnam ese ▁Army ) ▁fitted ▁a ▁small ▁number ▁of ▁M 1 1 3 ▁arm ored ▁personnel ▁carri ers ▁with ▁tur rets ▁taken ▁from ▁ob sole te ▁M 8 ▁Grey h ound ▁arm ored ▁cars . ▁ ▁Switzerland ▁▁ ▁Sch üt zen pan zer ▁ 6 3 ▁- ▁Design ation ▁of ▁the ▁basic ▁M 1 1 3 A 1 ▁in ▁Swiss ▁service . ▁ ▁Sch üt zen pan zer ▁ 6 3 / 7 3 ▁- ▁Vari ant ▁of ▁the ▁SP z ▁ 6 3 ▁with ▁a ▁front ▁float ▁panel ▁( found ▁on ▁the ▁M 1 1 3 A 2 ), ▁as ▁well ▁as ▁a ▁Swedish ▁H ag gl und s ▁tur ret ▁fitted ▁with ▁an ▁O er lik on ▁ 2 0 ▁mm ▁can non ▁Kan ▁ 4 8 / 7 3 . ▁ ▁Sch üt zen pan zer ▁ 6 3 / 8 9 ▁- ▁Up grade ▁of ▁the ▁SP