To understand how to adjust the weight of your Poison cue, you will first need to understand if there is already a weight bolt inside, and if so what is the length or weight of the weight bolt.
As you can see on the Poison weight bolts webpage, the current Poison weight bolts come in various weights (0.25 oz, 0.5 oz, 1.5 oz, 2 oz, 2.5 oz and 3.5 oz):
To access the weight bolt, the bumper can be unscrewed and the weight bolt can be removed with an Allen wrench.
Once its length or weight is known, you will be able to understand the range by which your cue weight can be adjusted. You can lighten the cue by the weight of the current weight bolt. You can also increase the weight by using a heavier weight bolt than the one currently in your cue. You can increase the weight at the maximum by calculating the difference between your current weight bolt weight and the longest weight bolt available that weighs 3.5 oz.
Since they do not have a head, the weight bolts can be stacked to get to the desired weight (for example using a 0.5 bolt, and then a 0.25 on top of it to add 0.75 oz). If stacking weight bolts, they will need to be tightened well together to prevent buzzing sounds.
The current Poison weight bolts are compatible with Poison cues made after 2015:
To find out when your cue was made, you will find the current models in the Pool Cues section of the Poison website and these models are using the new weight bolts: https://www.poisoncues.com/usa/pool-cues.html
If you cue is not a current model, you can find the year where it was released in the Retired Cues section of the Poison website: https://www.poisoncues.com/usa/pool-cues/retired-cues.html
If the release year is before 2015, then you cue is not compatible with the new Poison weight bolts.