SAM 2.1 Hiera Base Plus is a segment-anything model tuned for real-time object segmentation in images and video. It sits in the middle of the SAM 2.1 family — larger than the lightweight tiers but leaner than the full Large variant — offering a practical balance between segmentation accuracy and computational cost. It handles promptable segmentation tasks where you point, click, or box-select objects, and it tracks them across video frames.