Sonic pen

The sonic pen that Miss Foster had worked much like the Doctor's sonic screwdriver, but it looked like an ordinary pen. On the end, it featured the same glowing blue light as the sonic screwdriver. The Doctor activated it whilst pointing it directly at his own sonic screwdriver, creating a sonic feedback loop. Before doing so, he asked Miss Foster whether she was aware of what would happen when two identical sonic devices were used in such a way, implying that her pen and his screwdriver were manufactured at the same place, or at the very least share the same technology. The Sonic Pen was able to open deadlock seals in the Adipose Industries Headquarters.