Plug-in circuit breaker safety base only, for plug-in circuit breakers 6 amp to 32 amp. Although the new plug-in circuit breakers can be fitted directly to a lot of the older porcelain bases, to comply with current standards the porcelain base should be replaced with this matching plastic safety base. This base can often be fitted without drilling as procelain fuse bases (except 32 amp) have the same back entry and mounting hole. This product should only ever be fitted by a registered electrician.
Tip: It is often better value to consider a surface enclosure (or even a complete new distribution board) and modern circuit breakers when replacing porcelain fuses. If you are in doubt please send me a photo of your switchboard and I am happy to advise.