Based on this product's specifications, here are some alternatives and similar models
Battery Grip Pentax D-BG2 Lithium-Ion for K10D
Summary description:
The Pentax D-BG2 Battery Grip is designed for the K10D camera, featuring Lithium-Ion technology for reliable power. Weighing 235g, it enhances grip and stability, making it ideal for extended shooting sessions. The sleek black design complements your camera while providing additional battery life for uninterrupted photography.