Seismic is currently running an experiment at HAM3 to determine whether we want to use more viton on the HAM ISI. This means there are 3x 10kg masses that are not bolted down on the optical table. These masses are sitting on viton pads, while Hugo runs a transfer function. If sub-systems are entering HAM3, please watch out for these stacks, as moving them could disturb the balance of the ISI. The relevant stacks are pretty obvious as I put the old mounting bolts in the top masses, to keep the weight properly distributed, as pictured.