The C-cored chokes to the right image were recently made in Australia. Most have C-cores and are nicely layer wound, varnished and perfectly reliable. However, most require that the air gap must be set to suit the maximum wanted inductance at the required dc current.
The old chokes in the right image range in age from 60 years to 2 years. Because they are only chokes and not something more complex like a transformer, the are still very reliable and able to be used in any diy gear which calls for a choke or two and where appearance isn't important although all may be cleaned up and painted to look better. Some are potted and in sealed cans containing special oil. Some are military specification, some are normal open frame and some are badged AWA or Ferguson and have bell ended construction.
