Configuring A Route via GUI - MTU value

This more of a general question and not one where an issue is occurring. When I started looking at the possible configurations that can be done via the GUI for adding a route, I noticed that MTU is not a required field (version 12.1.2). However, there is a value of 0 by default. Now I doubt F5 would allow you to have a MTU of 0 so my question is...Is the default value of 0 in the MTU field the equivalent to 1500?