This is a cap/lid for a 250mL tri-pour beaker. Commercial caps for these types of beakers come in minimum lots of 100-500 and cost $50-100, so I designed my own using OnShape. The CAD source for this is freely available at: https://cad.onshape.com/documents/d82e8717aee3378daa5beb76 The specific beaker I measured and designed this for is the Globe Scientific model available for sale on Amazon at http://www.amazon.com/dp/B00G6SU94C However, it will likely fit other tri-pour beakers in a similar manner with just some XY scaling. I measured an approximately 8 degree draft angle and included it in the design, but since there are so few layers, I'm not sure it makes a big difference.