For a cricket bat suitable for hardball cricket with a bag size 3, here are some key features to consider:

1. Size and Weight: A size 3 cricket bat is typically designed for junior players, usually between the ages of 8 to 11 years old. It should be lightweight enough for a junior player to handle comfortably, typically ranging from 1 lb 10 oz to 2 lbs 3 oz (737 grams to 1000 grams).
2. Material: Look for a bat made from high-quality English willow or Kashmir willow. English willow is preferred for its superior performance, while Kashmir willow offers good performance at a more affordable price point.
3. Grains: The number of grains on the face of the bat can indicate the quality of the willow. More grains usually indicate better quality wood, but this isn’t always a strict rule.
4. Handle: The handle should be comfortable to grip and should provide good shock absorption. It should be made from high-quality cane or rubber, with a comfortable grip.
5. Sweet Spot: The sweet spot is the area on the bat where you get the best power and feel when hitting the ball. Look for a bat with a well-defined sweet spot, typically located slightly above the midline of the blade.
6. Toe Guard: A toe guard is a protective covering at the bottom of the bat. It helps prevent damage to the toe of the bat, especially during ground contact.
7. Edges and Profile: A thicker edge and a larger profile can provide more power to your shots. However, for junior players, it’s essential to find a balance between power and control, so a moderate edge size and profile might be more suitable.
8. Bat Bag: The bat bag should be durable and provide adequate protection for the bat during transport. Look for a bag with padding to protect the bat from damage.
9. Brand Reputation: Choose a bat from a reputable cricket equipment manufacturer known for producing high-quality bats. Some well-known brands include Gray-Nicolls, Gunn & Moore, Kookaburra, and SS Ton.

Before making a purchase, it’s a good idea to visit a sports equipment store to physically handle different bats and find one that feels comfortable and suits your playing style. Additionally, consider seeking advice from coaches or experienced players for recommendations.