This conductive material (also known as "Velostat" or "Linqstat") is a nice addition for your theyarable/sensor hacking toolkit. It's pressure-sensitive: squeezing it will reduce the resistance, so it's handy for making flexible sensors. And it's a lot less expensive than off-the-shelf pressure or bend sensors too! Each order comes with a 11"x11" (28cm x 28cm) 4mil (0.1mm) thick piece. Adafruit may fold the sheet into quarters to ship it to you. To remove any hard creases, simply lay flat on a table and put a heavy book on top to flatten it out.
This presentation from Hannah Perner-Wilson (plusea) has a lot of great ideas for how to use this material.
Pressure-Sensitive Conductive Sheet (Velostat/Linqstat) (7:44)
- Dimensions: 11" x 11" (280mm x 280mm)
- 4 mil / 0.1mm thick
- Weight: 18.66g
- Temperature Limits : -45°C to 65°C (-50°F to 150°F)
- Heat Sealable : Yes
- Volume Resistivity : <500 ohm-cm
- Surface Resistivity : < 31,000 ohms/sq.cm