These are the smallest commercially-available LEDs for use with LEGO®.  Our Micro LED Light Boards were small, but these Pico LED Light Boards are REALLY small: just 4mm in diameter.  They are round, so they will fit inside round bricks without sanding or modification.  They will also fit under bricks, plates, and tiles-- go ahead and snap any of these right on top of the LEDs.  Because they are also so thin, the LEDs can be mounted on top of LEGO studs.  Now there is hardly anything you can't light up Best of all, the Pico LEDs come in 8 colors Want to see these tiny LEDs in action?  Check out the videos in the "Product Videos" section.Use these Pico LEDs in any LEGO® project, on any model railroad layout of any scale, in Department 56® or Lemax buildings, in dollhouses, or in any robotics project to add detail and interest and capture that “wow” factor. No electronics or soldering knowledge is necessary to set up these lights and start using them right away. Use the included adhesive squares to easily mount the boards to almost any surface—put them anywhere in even the smallest structures. Use the included adapter board to create chains of light boards or light strips (sold separately)—connect 100 boards or more to add light to even the largest model project. Unlike other light modules that use 12 or 24 volts, these use 5 volts and are ready to use with any microcontroller or robotics project—no need for complicated resistor calculations The boards produce almost no heat, allowing for installation in the smallest spaces. NOTE: This kit includes two Pico LED Light Boards with 12" micro cables, one adapter board, and adhesive squares for mounting. No power source or connecting cables are included, but these can be purchased separately.  To use the Pico Light Boards, you will need to purchase a power source and (if connecting more than one set of Pico Light Boards) connecting cables. Details:Two Pico Light Boards (2 of a single color in each pack) and one adapter board to connect them to a power source (sold separately)Perfect for all hobby applications-- small size along with thin and flexible wire makes for easy installation into small spaces—the plug at the end of the Pico Light Board cable will fit through a standard LEGO® stud holeSelf-adhesive squares (included) allow mounting in just about any location or configuration5V DC operation means the light boards are also compatible with microcontroller or robotics projects (Arduino compatible)No soldering or electronics knowledge necessary—be up and running in minutes NOTE: This is not a LEGO® product.  LEGO® is a trademark of the LEGO® group of companies, which does not sponsor, authorize, or endorse this product.