Please pay close attention to dimensions. The photos make the Cholla appear larger than it is. Some of these pieces are quite small and suitable for even one-gallon tanks.
Boil the pieces for a couple of minutes and then soak in treated water. Cholla takes a while to sink so either leave it in the treated water or let it float in your tank.
I do not make money on postage so will refund any shipping overages of $2.00 or more. I will use whatever method is cheaper and will include tracking with each order. Shipping to Canada would be prohibitive for these pieces; however, if you're interested, I'll be glad to have the USPS weigh the one/ones you want and give you a cost.