It's a dual-core chip with an unlocked multiplier, a 4.2GHz base clock and 4MB L3 cache. Unfortunately, it looks like the 7350K will be absent from the desktop Kaby Lake launch lineup.
An exact launch date isn't known but expect a delay of several weeks. Pricing of this OC chip is expected to be around $175 and it should overclock to around 5GHz with nothing more than air cooling;
Expected to be priced at $175, the Core i3-7350K is expected to carry a base clock of 4 GHz, with 5 GHz on air being the expected OC potential of the chips. Apparently, Intel is delaying the launch of this part (as well as its entry-level Celeron and Pentium families of processors) by several weeks. This could be a way for Intel to prevent early cannibalization of its i5 7400 processors by a small chip that could, in the right scenario, provide much higher performance due to its 1 GHz extra base core clock speed (also being the only Core i3 desktop SKU to feature Turbo Boost, with a frequency of up to 4.2 GHz).