Heath is now taking orders for the single pole high pass filter both in kit form and as a complete unit. The price for both options is only $39 including Australian postage.
Fixed 20db cut to 30Hz and below
No Battery required
No Power needed
51 x 51x 32mm
Pictured below is the two pole unit with the switch on the front. The unit above will be single pole, without the switch. Honestly the 40db cut of the two pole position was way to much and of very little use in the real world.
Mod Edit: Payment Details added.
I (Heath) will PM all that want one with my bank details. No PayPal this time, please. Just make sure you add your name to the payment as reference, thanks.