Amazon has 1/4" x 3-1/2" x 6-1/2" Bosch Bulldog SDS-Plus Hex Drive Rotary Hammer Bit on sale for $4.99 – $0.75 off when you clip the coupon = $4.24. Shipping is free w/ Prime or on $25+ or $35+ orders (minimum requirement varies by location).
Product Description from Store
- Hex drive system for use with concrete screw drive sleeve
- 15 percent faster (compared to S4L)
- Bosch-made carbide tips are tougher and more durable under heavy loads
- Proprietary Bosch hardening process results in more holes per bit
- For varied applications in concrete