Resistors have three values that are of importance when doing basic mods. 1. Power Rating (Watts) You need to look at the power rating of resistors. This is usually seen by the size of the resistor itself. Typically, for the type of resistors we offer, the bigger the size the more power it can handle (more leds). 2. Resistance (ohms) This is the value that most people who are not familiar with resistor usually overlook. This is how restrictive the resistor is. The lower the number, the more overall current that can pass through it and the higher the less overall current that is allowed to pass through the resistor. 3. Tolerance This is probably not as important in lighting mods unless you are getting very specific with your numbers. Basically, the tolerance is a percentage of the resistor value that it is guaranteed to be within. For example, if you have a 100 ohm 1% tolerance resistor then it is guaranteed to be between 99-101 ohms. Respectively, if you have the same resistor, but a 5% tolerance then it is guaranteed to be between 95-105 ohms. We only carry 1% tolerance resistors. That way if you want to try and maximize the brightness of your leds you have that option to do some real fine calculations. Here are the resistors we offer: 1/4-1 Watt Metal Film Axial Lead Resistors [caption id="attachment_252" align="aligncenter" width="600" caption="Resistor Color Code Chart"]Resistor Color Code Chart[/caption] Here is an example on how to use the chart. If you have a resistor with these color bands on it here is how to read it (in order from left to right). Usually brown or gold will be on the right hand side because they indicate the tolerance. First Band: Orange - First Digit Second Band: White - Second Digit Third Band: Orange - Multiplier Fourth Band: Brown - Tolerance Your first digit will be: 3 Your second digit will be: 9 The multiplier will be: x10^3 Tolerance will be: (+-)1% Your resistor value will be 39 x 10^3 = 39,000 You will see this value resistor written as: 39k ohm 1% Note: 10^0 = 1 -------> so you will not add any zeros if your multiplier band is black.