[Knufire]

There was a laundry list of materials you were allowed to make minibots out of, quoted below.

Originally Posted by 2011 FRC Game Manual: R92

The following items are the only permitted materials for use on the MINIBOTS:

A. TETRIX components that are not in violation of any other rules, (Tetrix components are listed in Approved Tetrix Parts at www.usfirst.org/frc/competitionmanual),
B. no more than two motors (PN W739083/W739023) and an unlimited number of Tetrix servos),
C. no more than one 12V rechargeable NiMH battery pack identical to those supplied in the FTC kit of parts (PN W739057) except the 20A fuse may be replaced with an equivalent type of lower amperage,
D. No more than one HiTechnic DC motor controllers,
E. No more than one NXT controller with the Bluetooth functionality disabled,
F. Polycarbonate,
G. Polycarbonate glue,
H. Raw welding rod, aluminum sheet, 90° angle, u-channel, tube, bar, that is not sold in preperforated or pre-punched form.
I. rivets,
J. non-metallic rope or cord,
K. wire nuts, solder, and crimps,
L. cable ties,
M. limit switches,
N. no more than two common household light switches,
O. electrical hookup wire,
P. non-slip pad,
Q. PVC or CPVC pipe and fittings,
R. PVC cement or cleaner,
S. Mechanical fasteners (e.g. screws, bolts, etc),
T. Loctite or similar thread-locking product,
U. Rubber bands,
V. Surgical tubing,
W. Electrical tape and shrink tubing,
X. PWM extension cables,
Y. Universal security clips to hold the PWM connectors together,
Z. Hook and loop fastener (may not be used as tape),
AA. Magnets,
BB. NXT compatible sensors and related connectors/cables,
CC. Grease, and
DD. Non-functional decorations.

Non-slip pad was literally anything marketed as non-slip pad.