| Part No. | Where Used | Description | Value |
| 421-1 | O-7, O-11, HW-29, HW-30, RX-1, IP-2718, IO-10 | 3AG | 1.5 amp |
| 421-13 | SB-650 | 3AG | 0.5 amp |
| 421-2 | EC-1, DX-60, HA-201 | 3AG | 3 amp |
| 421-20 | SB-610, HO-10, HO-13, IT-11 | slow blow | 0.5 amp |
| 421-21 | HA-10 | 3AB | 15 amp |
| 421-22 | IG-18 | slow blow | .75 amp |
| 421-25 | EUW-15, IP-17, IP-27 | slow blow | 1.5 amp |
| 421-26 | HD-1481, EUW-15 | slow blow | 0.125 amp |
| 421-29 | SB-230 | 3AG slow blow | 0.75 amp |
| 421-3 | HA-20, TT-1 | 3AG | 2 amp |
| 421-32 | EUW-15 | 5 amp | |
| 421-33 | IB-1100, IB-102 | 3AG slow blow | 0.25 amp |
| 421-4 | CA-1, IP-10, DX-100, HR-20, HW-29, HW-30 | 8AG | 8 amp |
| 421-40 | SB-630 | slow blow | 3/16 amp |
| 421-5 | HX-10 | 3AG slow blow | 4 amp |
| 65-10 | HW-16 | circuit breaker | 3 amp |
| 65-14 | HP-13A | circuit breaker | 30 amp |
| 65-15 | SB-200, SB-201 | circuit breaker | 8 amp |
| 65-17 | HP-23C | circuit breaker | 2.92 amp |
| 65-20 | HP-13A | circuit breaker | 10 amp |
| 65-28 | SB-220, SB-221 | circuit breaker | 10 amp |
| 65-53 | SB-230 | rocker switch w/breaker | 10 amp |
| 65-59 | SB-230 | thermal circuit breaker | 15 amp |