Acer and ASUS unveiled their new Ultrabook devices on Tuesday.

ASUS Ultrabook
The ASUS “Real Ultrabook” will go head-to-head with Apple’s new 11-inch and 13-inch MacBook Air laptops. The ASUS X21 is available in 11-inch and 13-inch models starting at under $1,000. The low-end X21 features an 11-inch display, i5 processor and 128GB SSD. The high-end UX31 includes an i7 processor, 256GB SSD and a 13-inch display. The 11-inch model weighs just 2.2 pounds compared to Apple’s MacBook Air at 2.38 pounds.

Acer Ultrabook
Acer is also introducing its own Aspire range of Ultrabooks. The S3 series includes a 13-inch display, i5 processor and a hybrid 20GB SSD/320GB HDD system. The full Acer Aspire S3-951 salient specs (via CNET):
- Size: 0.51 inches thick, 2.98 pounds
- Materials: aluminum/ magnesium chassis
- Display: 13.3-inches, 1366×768
- Processor: Intel Core i5, 1.66GHz (power-efficient ULV)
- Graphics: Intel HD 3000
- Storage: 20GB SSD, 320GB HDD (hybrid design)
- Memory: 4GB
- Battery: rated by vendor at up to 6 hours
- Ports: USB 2.0 (2), HDMI, SD reader
- OS: Windows Home 7 Premium
- Price: $899.99