Boston   jack plug female, nickel, with spring 6,5mm, 2-pole

Switchcraft   jack plug, 6,3mm, 2-pole, nickel contacts

Switchcraft   jack plug, 6,3mm, 2-pole, nickel contacts, angled

Switchcraft   jack plug, 6,3mm, 3-pole, nickel contacts

Switchcraft   mini jack plug, 3,5mm 3-pole, nickel contacts