Holo Glasses is the singular item added by Holo Inventory. When equipped to the Tinker's Construct mask slot, any inventory looked at will show an overlay of its contents, with item icons and quantities. The overlay can be toggled with a keybind (default NUMPAD5), set under Esc > Options > Controls > HoloInventory > HoloGlasses. HoloInventory is integrated with NEI and will filter its displayed items if Search mode is active (double-click the NEI search box to apply a yellow border). This can be very helpful for locating lost items or tools without having to open each individual inventory or machine.

Single-piece black sunglasses with dark grey arms.
Multiple rows of decorative block icons with white numbers at the bottom of each, overlaid on a silver chest and a dull grey-pink background.
Chest contents shown with HoloGlasses

Known issues

HoloGlasses must be equipped via the Tinker's Construct inventory tab (Inventory > Diamond Chestplate tab, above avatar). While the Traveller's Gear inventory tab (Inventory > Book icon in avatar box) has a mask slot, equipping Holo Glasses here does not make them function properly.