Following examination, TPG companies typically encapsulate the currency in what is commonly referred to as a "slab." Similar to the issues surrounding the transition that occurred within the coin collecting field many years ago, controversy exists about the need or value of TPG notes. Without having the ability to closely examine and feel the note due to it being sealed inside the slab, many collectors are not comfortable accepting the opinion of others as to the grade and may either elect not to purchase the note or to cut it out of the slab for examination. Additionally, many noted mistakes in grading by third party grading services have been discovered. However, for collectors less adept at grading, purchasing a note in a slab can provide some additional comfort for the owner in justifying the purchase and cost. It also serves to help protect the collector against unethical activities designed to increase the worth of the note by pressing out folds, washing, repairing tears, or other alterations typically viewed as unacceptable thereby lowering the value of the item.