A bunch of SIM-free unlocked Sony Xperia smartphones have gone on sale in the US on Sony’s official online store – the Xperia acro S, Xperia miro, Xperia tipo, and Xperia tipo dual, though the miro and tipo dual are expected to ship in the first week of October unlike acro S and tipo which are available for immediate delivery.

The acro S is the high-end member of the new group and costs $649.99, with specs that include a 4.3″ 720×1280 pixels LED-backlit LCD display with Sony Mobile BRAVIA Engine, a 1.5GHz dual-core Snapdragon S3 processor with 1GB RAM, 12 MP camera with 1080p video recording, 1.3 MP front camera with 720p video, 16GB internal storage with up to 32GB microSD cards, a 1910 mAh battery, and Android 4.0 Ice Cream Sandwich. It’s available in both black and white colours.

The Xperia tipo and its dual-SIM sibling tipo dual will set you back $189.99 and $209.99 respectively, with entry-level specs including a HVGA 3.2″ display, 800MHz Cortex A5 processor, 512MB RAM, 2.9GB internal storage with microSD support, 3.15MP camera, 1500 mAh battery, and Android 4.0.3. The tipo is available in Classic White, Navy Blue, Deep Red and Classic Black colours, while the tipo dual comes in Serene Black or Classic Silver.

Finally we have the Xperia miro, which is priced at $239.99, whose specs are similar to the tipo duo, except for a 5MP camera, a bigger 3.5″ display (again of HVGA resolution), and 4GB of storage. The miro is available in Metal Black, Pink/Black, White and White/Gold colours.

Off-contract outright purchases aren’t too preferred in the United States, so unless these devices get offered by carriers on subsidized prices, they might not see too many sales. Are you interested in either of the four devices? Do let us know in the comments.