As a former photography student, I know that taking good care of your lenses is paramount. After shelling out a few hundred for a DSLR telephoto lens, you want to make sure that its as secure as Fort Knox before taking it anywhere. But sometimes it hurts to spend another $50-$100 buying something designed for the task after making the already hefty investment in the camera, lens and equipment.

Thankfully, marcellahella over at instructables.com has found a neat, and, more importantly, cheap way of securing your valuable lenses for only a few dollars by using plastic bottles. This quick and simple DIY project just requires two plastic bottles of the same shape that are large enough in circumference to hold the lenses, a foam or spongey material, dental floss, scissors, a safety pin, a zipper, a needle, and an optional innertube used to waterproof the container after you’re done.

All you need to do is cut the bottom of one plastic bottle to be slightly longer than the lens, and the other to be around 1 cm from the bottom of the bottle. Then, use the safety pin to make holes around the edges of both bottles, and proceed to use the needle and dental floss to sew halves of the zipper to the “lid” bottle and “container” bottle (dental floss is stronger than regular thread). Next, cut two circles of foam for the top and bottom portions of the bottles, and one rectangular piece of foam to line the edges. After placing them inside the bottles, you can choose to glue the pieces to the plastic or simply let them sit as marcellahella suggests. Lastly, the innertube can be cut and sewn together to be wide enough in circumference to tightly fit around the seam of the bottle in order to make the package waterproof.

That’s it! For step by step instructions and pictures, view the whole DIY project at Instructables.