I got this one. I love that it folds down. My daughter is only five months and not rolling over yet, but it makes me feel better having it there just in case, since she sleeps on my side.
Amazon, I got this one: Toddler Bed Rail Guard for Kids... https://www.amazon.com/dp/B01E8JP3TG?ref=ppx_pop_mob_ap_share
I would say it's not safe for a small baby to roll into as there's a bit of a gap between it and the bedframe, but I put a pillow against it to cover the gap.
It is! It's on sale on Amazon https://www.amazon.com/dp/B01E8JP3TG/ref=cm_sw_r_cp_apa_fabc_tBdQFb6HBF4N5?_encoding=UTF8&psc=1