VEVOR Safety Bollard, 36x5.5 Safety Barrier Bollard, 5-1/2" OD 36" Height Yellow Powder Coat Pipe Steel Safety Barrier with 4 Free Anchor Bolts for Traffic-Sensitive Area

Based on the product description, it is suitable for installing on uneven surfaces. The bollard comes with a base size of 7.9 x 7.9 inches and a thickness of 0.2 inches, which helps keep it stable on uneven surfaces.

While the product information does not explicitly mention filling the base with concrete, it does state that the base is sealed to prevent sand or cement leakage and increase stability. This sealed bottom design suggests that the base is not intended to be filled with concrete. However, the robust steel construction and anchor bolts provided should offer sufficient stability for most applications.

While the product description doesn't mention visibility in low light, customers find it highly visible. The bright yellow color with black stripes enhances visibility and safety in any lighting condition, according to reviews.

The product description states it has a "yellow powder-coated surface with a black stripe" that "resists rust, fading, and UV damage."

The top can not come off to allow for filling with sand or concrete.