93943 McCulloch Main Diaphragm NOS Original PRO MAC 800 and 850.  Part of Repair Kit, P/N 217082 and Gasket/Diaphragm Kit, P/N 216724.

Fits these McCulloch models:

11-600072A PRO MAC 800 08/80 to 09/81 IPL 213799-R1
11-600072B PRO MAC 800 08/80 to 09/81 IPL 213799-R1
11-600072D PRO MAC 800 08/80 to 09/81 IPL 213799-R1
11-600072E PRO MAC 800 08/80 to 09/81 IPL 213799-R1
11-600072F PRO MAC 800 08/80 to 09/81 IPL 213799-R1
11-600072J PRO MAC 800 08/80 to 09/81 IPL 213799-R1
11-600119B PRO MAC 805 08/82 to 06/95 IPL 216167-R3
12-600439D PRO MAC 850 04/77 to 08/80 IPL 93715-R6
13-600439A PRO MAC 850 04/77 to 08/80 IPL 93715-R6
13-600439B PRO MAC 850 04/77 to 08/80 IPL 93715-R6
13-600439D PRO MAC 850 04/77 to 08/80 IPL 93715-R6
13-600439E PRO MAC 850 04/77 to 08/80 IPL 93715-R6
13-600439J PRO MAC 850 04/77 to 08/80 IPL 93715-R6
14-600439A PRO MAC 850 04/77 to 08/80 IPL 93715-R6
14-600439B PRO MAC 850 04/77 to 08/80 IPL 93715-R6
14-600439D PRO MAC 850 04/77 to 08/80 IPL 93715-R6
14-600439E PRO MAC 850 04/77 to 08/80 IPL 93715-R6
14-600439F PRO MAC 850 04/77 to 08/80 IPL 93715-R6
14-600439J PRO MAC 850 04/77 to 08/80 IPL 93715-R6