Subnet Mask is an iPhone application developed by Takahiro Furuya. It falls under the category of Business & Productivity and is available for free.

Designed as a handy keypad, Subnet Mask allows users to easily calculate and visualize subnet masks using CIDR notation. With a simple tap, users can view the subnet mask and the number of host addresses. The application also offers swipe functionality, allowing users to manipulate the keys like a slider.

In addition to its primary purpose, Subnet Mask can also be transformed into a keypad for wildcard masks. By making this switch, users can view the wildcard mask and the corresponding number of addresses.

Overall, Subnet Mask provides a convenient and intuitive way to work with CIDR notation and wildcard masks. Its user-friendly interface and essential features make it a useful tool for network administrators and anyone involved in subnetting.