A little care in packing will prevent shipping and handling damage to the lower frequency coils that are used with the Eico 710 Grid Dip Oscillator (GDO). This is a hint from my experience in shipping EICO 710 coil sets. The A, B, & C lower frequency coils need a little extra internal protection. They are the ones with the coil and slug inside the plastic form instead of the wire wound on the outside. The internal coil is just held with a bit of glue or wax to the fiber end cover of the coilform. After a few decades it may be dried and ready to let go. Just a little shake and bounce in shipping will pop the coil loose and then it flops around inside the plastic form. That can break a lead wire. What I did is gently push a little soft packing foam up inside the pin end of the form so it padded the bottom of the coil and slug. Then the coil will stay inplace. Anyway, that is how I repaired a set I got that was loose and flopping about. I have not seen the same problem with the low frequency coils for the: Heathkit GD-1 A/B Grid Dip Meter, Millen 90651 GDO family, Measurements Model 59LF Grid Dip Meter, (The 59LF coils have a different weakness, the top end of the coil [opposite the pins] should be taped or held down to prevent it popping out the end and to prevent the inner parts of the coil from rotating in the plastic form. The weight of the iron core makes them vulnerable to shake, rattle, & roll.) There is no current production of these items; if they are not cared for, they will become unusable and unavailable. Free hints may be worth what they cost..... bill.mays