Both firm and extra firm tofu can be used to make tofu meatballs, but the choice between the two depends on the texture you're aiming to achieve in your meatballs. **Firm Tofu:** Firm tofu has a slightly higher moisture content and a softer texture compared to extra firm tofu. It can work well for tofu meatballs if you're looking for a more tender and delicate texture. Firm tofu will be easier to mash and blend with other ingredients, resulting in a softer and more melt-in-your-mouth type of meatball. **Extra Firm Tofu:** Extra firm tofu has a lower moisture content and a denser, firmer texture. It holds its shape better and can withstand more handling and cooking without breaking apart. If you're aiming for meatballs with a chewier and more substantial texture, extra firm tofu would be a good choice. It will retain its shape and provide a more defined bite. Ultimately, the choice between firm and extra firm tofu for making tofu meatballs depends on your personal preference for texture. You can experiment with both options to see which one aligns better with your desired outcome. If you're unsure, you might even try a combination of both to achieve a balance between tenderness and firmness in your tofu meatballs.