Instruction: Carefully assess the user's review for any strong expressions of sentiment, either positive or negative. Based on your analysis, select the most fitting sentiment option from the provided list as output.

Input:
They are identical in shape, and size to the Glock 42 factory sights. But give you a huge sight advantage in low light night conditions. While there are other more expensive fiber optic tritium models available. From TRUGLO, Trijion, Ameriglo and others, don't waste your money. The TRUGLO Brite-Site Tritium Night Sights, are the most effective best value available. But I would strongly suggest that you take them to a Gunsmith for instillation, to avoid damaging your pistol.

Options:
A: very positive
B: positive
C: neutral
D: negative
E: very negative
Answer: A: very positive