I’m a new owner. I bought mine used. I bought this portafilter basket. It’s really nice. IMS Competition E-61 Precision Filter Ridgeless Basket 18/22 gr - B70 2TC H28.5 E https://www.amazon.com/dp/B01L81YUBO/ref=cm_sw_r_cp_tai_s69pEbA8NQH03 there are different sizes. I wanted IMS and ridgeless.

Edit: thought you meant basket. Bottomless- there’s factory cut, there are some not cut enough so they’re not quite bottomless and there’s handles. I wanted something that I could put a custom handle on. A lot buy this one but the handle isn’t replaceable Bottomless Portafilter Gaggia with 3 Cup Filter Basket 21g https://www.amazon.com/dp/B00KRR4K2K/ref=cm_sw_r_cp_tai_..9pEbZXY4CS7