The E-1 connector uses a unique center pin that is hollow. This allows the high purity Copper cable, that is carrying the signal, to slide all the way through the center pin and puts less connecting material in the signal path than any other connector on the market.
Lengths and prices are:
.5 meter pair $199.1.0 meter pair $215.1.5 meter pair $230.2.0 meter pair $245.