they sell them on amazon for $20 which is about the same price you'd get it from dhgate. let me find both links; i'll edit this when i do
After searching my Dhgate, it looks like both items (from 2 different sellers) were removed from the store. Not entirely certain why
E2: looks like dhgate on pc is returning network errors. Links fixed
I would recommend one of the oval shaped guys over the tubes.. but they both work well. The latter holds more water.. heres the tube. https://www.amazon.com/dp/B0797NWYNY/ref=cm_sw_r_cp_apa_i_PejvFbJX6GJRB And here is the bottom one .. i actually only use this one on my regen as it works great.. https://www.amazon.com/dp/B07PR25GPZ/ref=cm_sw_r_cp_apa_i_3fjvFbEY4HRFP Good luck out there:) and , The Regen might not get much love on this sub, but hey, it works.