
REGISTRY

Heyco 3086 POP-1000 PRY OUT HOLE PLUG 1" BLACK - For most first gen Reference amps including 405, 604, 500, 300, 200 and possibly others. Will NOT fit Continuum's smaller switch holes (see BPF-1)

CAPLUGS BPF-1 3/16 Hole Plug Low-Density Polyethylene flush-type heads - Fits most first gen Reference amps, can be used instead of Heyco 3086.
You can find these on eBay too

CAPLUGS B-804 - All Reference S, Class A and USA amps with oval window bottom cover. Will fit Reference 705 and The Continuum. Does not fit all ovals.
https://www.ebay.com/usr/originalparts_nos
(may no longer be in business?)

CAPLUGS BPF-1 1/2 black LDPE plastic flush button plugs - some first gen Reference amps. e.g 604 (requires 3 plus 1 Heyco 3086). Also fits Reference 705 and The Continuum.
You can find these on eBay too

CAPLUGS BPF-1 black LDPE plastic flush button plugs - some first gen Reference amps. Will fit The Continuum (for the two smallest holes). May fit 705 as well.
These are rare, you cannot find these on CAPLUGS website

Metal 3/8-32 Hex Nuts & washer nickel plated for CTS and Switchcraft with 3/8"/32 thread and also for RCA jacks on old school Soundstream amps. e.g. most Reference series amps.