WIREMOLD SOURCE I® SERVICE FITTINGS Source 1 Series Service Fittings Ordering Information (continued) S1MC Mudcap 897AR Adjusting Ring For Source I 437 Attaching Ring. 4" [102mm] O.D. S1MC-MS Mudcap For Source I Attaching Ring with marker screw. 4" [102mm] O.D. Use with 437 Attaching Rings only. 439 Attaching Ring INFLOOR DUCTS For polycarbonate afterset use only. No adjusting ring required. 4" [102mm] O.D. Four #6-32 hold-down screws provided. 592 WWW.LEGRAND.US/WIREMOLD Adjusting ring (with three adjusting screws) for use with 437 Attaching Rings - power for brass fitting only. 3 25/32" [96mm] O.D. 898AR Adjusting Ring Adjusting ring (with three adjusting screws) for use with 437 Attaching Rings - communication only (brass and polycarbonate fittings) and power for polycarbonate fitting only. 3 25/32" [96mm] O.D. S1ER Extension Ring Extension ring - mounts on top of 437 Attaching Ring. Includes extension ring and three mounting screws. 4" [102mm] O.D. Add suffix to indicate ring height: 7/8", 1 1/8", 1 1/2", 2", 2 3/8", 3 1/8". We recommend using a shallow Attaching Ring and deep extension ring whenever possible.http://WWW.LEGRAND.US/WIREMOLD