There are no accidents, only Flukes.
The Multimeter is a tool added by Thermal Expansion. It can be used to look up information from various types of blocks in the world.
Using the Multimeter on a block in the world will display any information that block has to offer via chat. This will only work on blocks that explicitly support this.
The following blocks from the CoFH mods support Multimeter information lookups:
|Any Machine||Stored energy|
|Autonomous Activator||Stored energy|
|Caches||Item type, item amount, locked/unlocked|
|Portable Tanks||Fluid type, fluid amount|
|Energy Cells||Stored energy|
|Fluctuating Itemduct||Stored residual energy|
|Flux-Plated Fluiduct||Stored residual energy|
|Fluxducts||Stored residual energy|
|Fluid Tank||Fluid type, fill percentage|
|Plastic Pipe||Is powered, fluid type, fluid amount, saturation|
|RedNet Cable||Colors per side|
|RedNet Energy Cable||Colors per side, energy saturation|
Other mods may also add Multimeter support on their blocks using the CoFH API in CoFHLib.