BATTERY BOLT-12V 5MAH

lead-acid motorcycle battery. Based on the photo and the typical specs for this model, here is a breakdown of what you're working with:
​Battery Specifications
​Voltage: 12V
​Capacity: 5Ah (Amp-hours) at a 10-hour rate.
​Type: AGM (Absorbed Glass Mat) / Maintenance Free.
​Polarity: Looking at the front (as in your photo), the Negative (-) terminal is on the left and the Positive (+) is on the right.
​Safety & Maintenance Tips
​Since I see some tools and an engine casing in the background, here are a few things to keep in mind while you're working:
​Charging: If you need to charge it, use a smart charger or "battery tender" specifically designed for AGM batteries. Avoid using high-amperage automotive chargers, as they can cook a small 5Ah battery quickly.
​Storage: If the bike is going to sit for more than a couple of weeks, disconnect the negative terminal or keep it on a maintainer. Small motorcycle batteries lose their charge relatively fast.
​Terminal Cleanliness: Ensure the terminal bolts are tight and free of corrosion (that white powdery stuff). A bit of dielectric grease can help prevent future oxidation