I made a Flex Sensor!

I made a DIY Flex Sensor which I found an Instructable for. Its not very accurate but does show a change in reading I'm going to find out if its possible to calibrate it and smoother more useful readings. Its pretty cool that it actually works. 

In the tutorial they use Non static black poly bag which i searched all over for but couldnt find. But it seems regular thickish black poly bag works ok enough.